System practice problems

System Practice Problems

Answers

Answer 1

Looking at the first system of equations,

16x - 10y = 10

-8x - 6y = 6

If we multiply both sides of the second equation by 2, the coefficient of x is exactly the negative of the coefficient of x in the first equation.

-8x - 6y = 6

⇒   2 (-8x - 6y) = 2 (6)

⇒   -16x - 12y = 12

By combining this new equation with the first one, we can eliminate x and solve for y :

(16x - 10y) + (-16x - 12y) = 10 + 12

⇒   -22y = 22

⇒   y = -1

Then we just solve for x by replacing y in either equation.

16x - 10y = 10

⇒   16x - 10 (-1) = 10

⇒   16x + 10 = 10

⇒   16x = 0

⇒   x = 0

The main idea behind elimination is combining the given equations in just the right amount so that one of the variables disappears. The "right amount" involves using the LCM of the coefficients of a given variable. In this example, the x-coefficients had LCM(8, 16) = 16, so we only had to scale one of the equations (the one with -8x) to cancel all the x terms.

If we wanted to eliminate y first instead, we first note that LCM(6, 10) = 30. To get 30 as a coefficient on y, in the first equation we would have multiplied by 3:

16x - 10y = 10

⇒   3 (16x - 10y) = 3 (10)

⇒   48x - 30y = 30

And in the second equation, we would have multiplied by -5 (negative so that upon combining the equations, we end up with -30y + 30y = 0):

-8x - 6y = 6

⇒   -5 (-8x - 6y) = -5 (6)

⇒   40x + 30y = -30

Now combining the two scaled equations gives

(48x - 30y) + (40x + 30y) = 30 + (-30)

⇒   88x = 0

⇒   x = 0

We then solve for y :

16x - 10y = 10

⇒   -10y = 10

⇒   y = -1

so we end up with the same solution as before.


Related Questions

10/11 x 3/7 x 1/2 Multiply. Write your answer as a fraction in the simplest form.

Answers

The simplest form to this equation would be 15/77

please mark me brianliest if i was correct!

Fractions are written as a ratio of two integers. The product of the fractions in its simplest form is 15/77

Simplification of fractions

Fractions are written as a ratio of two integers

Give the expression

10/11 x 3/7 x 1/2

This can also be written as:

10/2 * 1/11 * 3/7

= 5/11 * 3/7

= 15/77

Hence the product of the fractions in its simplest form is 15/77

Learn more on fractions here: https://brainly.com/question/78672

#SPJ2

Please help this is due on Monday! Will give brainliest!!!!

Answers

Answer:

The awnser in the first option. A

A half circle is joined to an equilateral triangle with side lengths of 12 units.

What is the perimeter of the resulting shape? Type your answer in the box below.

Answers

Answer:

P = 12 pi units + 24 units.

Step-by-step explanation:

All sides of an equilateral triangle are of the same length.  Here that length is 12 units.  We take a circle of diameter 12 units and cut it in half through its center.  Finally, we join the triangle (remembering that all of the side lengths are 12 units) to the half circle of diameter 12 units.

The half circle portion of the resulting shape has circumference 2(pi)(12 units) divided by 2, or 12 pi units.  This is half the formula C = 2(pi)(r).  The two non-attached sides of the triangle have a total length of 24 units.

Thus, the perimeter of the resulting figure is P = 12 pi units + 24 units.

helppppppppppppppppppppppppppppp

Answers

Answer:C

Step-by-step explanation:

I seraph it up

Answer:

Latisha works x hours a day.

No. of hours Demetrius works = x+1 a day.

No. of working days a week = 5

No. of hours Demetrius works weekly =

= 5(x+1)

which can also be written as 5x+5

So the c option is correct.

what is .9 repeating as a fraction

Answers

There is no answer to this because:

Any digit repeating like that would usually be ?/9

Example: 0.1 repeating = 1/9

                0.2 repeating = 2/9

                0.8 repeating = 8/9

But 0.9 repeating? There should not be a fraction for that.

If you want to round up to 1, you can.

25.4 as mixed number

Answers

Answer:

6.25

Step-by-step explanation:

I believe you were trying to put a fraction in but accidentally pressed the period.

25/4

6 1/4

6.25

Answer:

25 2/5

Step-by-step explanation:

Hope it's right and it helps.

7 1/3 x 7/11
simplify the answer completely and change to a mixed number

Answers

Answer:

Hello There!

Your question says that

[tex]7 \frac{1}{3} \times \frac{7}{11} [/tex]

Now lets convert mixed fraction to improper fraction

[tex]7 \frac{1}{3} \\ \\ so \: 7 \times 3 + 1 = 22 \\ \\ so \: \frac{22}{3} [/tex]

Now let's simplify..

[tex] \frac{22}{3} \times \frac{7}{11} \\ \\ [/tex]

Now simplify 22 and 11 so it will look like

[tex] \frac{2}{ 3} \times \frac{7}{1} \\ \\ multiply \: \frac{2 \times 7}{3 \times 1} \\ \\ = \frac{14}{3} [/tex]

Now lets convert it to mixed fraction...

[tex] \frac{14}{3} = 4 \frac{2}{3} \\ \\ [/tex]

So it is the answer

[tex]4 \: \frac{2}{3} \\ \\ [/tex]

I hope it is helpful to you..Cheers!______

The product of the two given fraction is [tex]4\frac{2}{3}[/tex].

The given fractions are [tex]7\frac{1}{3}[/tex] and [tex]\frac{7}{11}[/tex].

Product of two fractions = Product of their numerators / Product of their denominators.

Here, [tex]7\frac{1}{3}[/tex] × [tex]\frac{7}{11}[/tex]

= [tex]\frac{22}{3} \times\frac{7}{11}[/tex]

= [tex]\frac{2}{3}\times\frac{7}{1}[/tex]

= [tex]\frac{14}{3}[/tex]

In mixed fraction [tex]4\frac{2}{3}[/tex]

Therefore, the product of the two given fraction is [tex]4\frac{2}{3}[/tex].

To learn more about the product of two fractions visit:

https://brainly.com/question/7335118.

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ANSWER IT!!! I ONLY HAVE MINUTES ​

Answers

Answer:

D

Step-by-step explanation:

5 + n is the sum of 5 and a number

amd then "less than or equal to -7" represents the no more than -7

Answer:

D

Step-by-step explanation:

To the moderator that deleted my answer, that was not necessary in the slightest. Go back to reporting bots, not removing correct answers that are put there to help people

Find the equation of a line that passes through the point (-4,1) and has a gradient of 2.
Leave your answer in the form
y=mx+c

Answers

Y=2x+9 it’s hard to explain but I’m pretty sure this is the answer

what regular polygon has an interior angle of 156 degrees

Answers

Answer:

regular pentadecagon

Step-by-step explanation:

it has 15 sides

that is what matches the exterior angled sum property - 360degree

let me explain it

1 side = 180 - 156 = 24

360/24 = 15

mark me brainliest and thank me if you like the answer

Y=-3x+1 y+5=-3(x-2) what do the following two equations represent A)The same line B)Distinct parallel lines C)Perpendicular Lines D)Intersecting, but not perpendicular lines

Answers

Answer:

C) perpendicular lines

number 4 plssss!!!!!!!!!!

Answers

Answer:

AB = 21

Step-by-step explanation:

Tales' theorem

[tex]\frac{12}{14} =\frac{18}{AB}[/tex]

[tex]AB=\frac{(14)(18)}{12}[/tex]

[tex]AB=21[/tex]

Hope this helps

(i)Given that:

AE || BD

AB = ? [Let AB be x]

BC = 3

ED = 12

DC = 4

We know that

By Basic Proportionality Theorem,

AB/BC = ED/DC

On substituting these values in the above formula

⇛ AB / 3 = 12 / 4

On applying cross multiplication then

⇛ x(4) = (12)3

⇛ 4x = 36

Shift the number 4 from LHS to RHS.

⇛ x = 36÷4

⇛ x = 36/4

Therefore, AB = 9

Answer: The value of AB for the given problem is 9.

Similarly,

(ii) Given that:

EB || DC

AE = 14

ED = 12

AB = ? [Let AB be X]

BC = 18

We know that

By Basic Proportionality Theorem,

AE / ED = AB / BC

On substituting these values in the above formula

⇛ 14 / 12 = x / 18

On applying cross multiplication then

⇛ 14(18) = (12)x

⇛ 252 = 12x

Shift the number 252 from LHS to RHS.

⇛ X = 256÷12

⇛ X = 21

Therefore, AB = 21

Answer: The value of AB for the given problem is 21

Additional comment:

Basic Proportionality Theorem

" A line drawn parallel to the one side of a triangle intersecting other two sides at two different points, then the line divides the other two sides in the same ratio".

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We need to use 60 yards of fencing to enclose a rectangular shaped garden the length is 30 yards less than twice the width. Find the dimensions of the garden.

Answers

Answer:

W = 16 2/3 yards

L = 3 1/3 yards

Step-by-step explanation:

A rectangle will consist of two sides with length L, and two more sides with length W.  Area will be W*L.

We are told that L is 30 yards less than 2W:

L = 2W - 30

We also learn that we have 60 yards of fencing for the perimeter, which is 2L + 2W.

Therefore, we can write:  2W + 2L = 60 yards.

I see the words "need to use," so I must conclude that all of the fencing must be used.  This sounds like a domestic issue.

Let's use L=2W-20 in the equation 2W + 2L = 60:

2W + 2L = 60

2W + 2(2W-20) = 60

2W + 4W-40 = 60

6W =100

W = (100/6) = 16 2/3 yards

L = 2W - 30

L = 2(16+(2/3)) - 30

L = 33 1/3 - 30

L = 3 1/3 yards

===============

Is the length 30 yards less than twice the width?

2W = 33.33

33.33 - 3.33 = 30 yards  YES

The formula to convert degrees Fahrenheit to degrees Celsius is: 'C = (5/9) ('F -32). The formula to convert degrees Celsius to degrees Fahrenheit is: 'F = 1.8 ('C) + 32. Using any of these formulas, determine, for what temperature the value of it in degrees Celsius is represented by the same number as its value in degrees Fahrenheit. Show your work. HINT: use either of those two equations, use x for 'C and use x for 'F, and solve it for x. The solution will be the answer to the problem (because the temperature is the same, and its numerical value in degrees Celsius in this case is the same as its number value in degrees Fahrenheit). *

Answers

Step-by-step explanation:

5/9 × (x - 32) = 1.8 × x + 32 = 9/5 × x + 32

5×(x - 32) = 9×9/5 × x + 32×9

5×5×(x - 32) = 9×9×x + 32×9×5

25x - 32×25 = 81x + 32×45

32×(-25 - 45) = 56x

4×(-70) = 7x

x = 4×(-10) = -40

-40° is the same temperature in Celsius and in Fahrenheit.

you roll a die 100 times and a six shows up 74 times out of 100. based on these outcomes, what is the estimated probability that the next roll shows up as a six?

Answers

It is 74% or 74 by 100 or 0.74

Solve 4,200 ÷ 70 = ________. Rewrite as a fraction to help you.

Answers

4200/70
take out a zero on both top and bottom

420/7
Simplify

= 60

Hope this helps!
Brainliest and a like is much appreciated

where dp you see yourself in the future?

Answers

Answer:

Happy

Step-by-step explanation:

mao I wanted to unalive myself not to long ago

Your friend has $100 when he goes to the fair. He spends $10 to enter the fair and $29 on food. Rude lady at the fair cost $2 per rude. Which function can be used to determine how much money he had left over after x rides?

Answers

Answer:

y=-2x-39

Step-by-step explanation:

Answer:

100=39+2x

Step-by-step explanation:

hoped that hedlp:P

PLEASE HELP MEEEEEEEE
Step 6: Problem solving with presents

a) If the sales tax is 7% on all purchases, how much must you set aside for sales tax on $300? Show your work. (2 points)

Answers

7% of 100= 0.07
$300x0.07=$21
$300 of 7% sales tax is $21
$300+$21=$321 total purchase

given the polynomial 6x^4+3x^3-7x^2+4x+5 choose all the following statements that are true?




A. The polynomial has a degree of 6

B. The polynomial has a leading coefficient of 4

C. The polynomial has 4 terms

D. The polynomial has a degree of 4

E. The polynomial has a leading coefficient of 6

Answers

Answer:

D and E are true

Step-by-step explanation:

The degree of a polynomial is the value of the largest exponent of the variable within the polynomial, that is the term

6[tex]x^{4}[/tex]

Thus the polynomial is of degree 4 → D

The leading coefficient is the coefficient of the variable with the largest exponent, that is

6[tex]x^{4}[/tex]

The leading coefficient is 6 → E

Find the solution(s) for x in the equation below.
x2 – 25 = 0

Answers

Answer:

x=5,-5

Step-by-step explanation:

how do I do this question?

Answers

Answer:

x = (y +2)/3

Step-by-step explanation:

y= 3x-2

y+2=3x

x=(y +2)/3

Check whether (19/9, 15/3) is
a solution of the equation 3a + b = 8 or
not where (a,b) is co-ordinate point.​

Answers

Answer:

No, it is not a solution to the equation.

Step-by-step explanation:

If [tex]( \frac{19}{9} , \frac{15}{3} )[/tex] is a solution of the equation, the left-hand side (LHS) of the equation would equal to the right-hand side (RHS) of the equation.

3a +b= 8

When a= [tex] \frac{19}{9} [/tex], b= [tex] \frac{15}{3} [/tex],

LHS

= [tex]3( \frac{19}{9} ) + \frac{15}{3} [/tex]

[tex] = \frac{19}{3} + \frac{15}{3} [/tex]

[tex] = \frac{34}{3} [/tex]

[tex] \frac{34}{3} ≠8[/tex]

Since the left-hand side is not equal to the right-hand side of the equation, [tex]( \frac{19}{9} , \frac{15}{3} )[/tex] is not a solution of the equation.

Given equation is 3a+b = 8

Given point = (19/9,15/3)

Put a = 19/9 and b = 15/3 in LHS of the given equation then

⇛ 3(19/9)+(15/3)

⇛(19/3)+(15/3)

⇛ (19+15)/3

⇛ 34/3 ≠ 0

LHS ≠ RHS

Given point not satisfies the given equation

Therefore, it is not the solution of the given point.

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lus
Suppose that y varies directly with x
and y = 10 when x = 20. What is y
when x = 15?
Enter your answer as a simplified fraction.
y =

Answers

Answer:

15/2

Step-by-step explanation:

y varies directly as x can be written as:

y & x

y = Kx

K = y/x

But from the question, we were told that:

y = 10

X = 20

K = y/x

K = 10/20

K = 1/2

The formula for the expression is:

y = Kx

y = 1/2 x

Now let us solve for y, when:

x = 15

y = 1/2 x

y = 1/2 x 15

y = 15/2

Answer:

When x = 15, y = 15/2

Step-by-step explanation:

Formula:  "y varies directly with x" comes out to y = kx symbolically.

Find the value of the constant of proportionality, k:  If y = 10 when x = 20, then this relationship becomes 10 = 20k, and k = 1/2.

Then the formula is y = (1/2)x.

When x = 15, y = 15/2

6 divided by 4 write your answer in a decimal form

Answers

The answer should be 1.5

Answer:

1.5

Step-by-step explanation:

Four goes into six once, then four goes into 20 5 times

Complete the table if x & y vary inversely

Answers

Answer:

(. ❛ ᴗ ❛.)(. ❛ ᴗ ❛.)(. ❛ ᴗ ❛.)(. ❛ ᴗ ❛.)(. ❛ ᴗ ❛.)

2. Graph each inequality on a number line:

5x + 15 < 0

Answers

Answer:

x < -3

Step-by-step explanation:

1. To put this inequality on a number line, we first must solve it.

Step 1: Subtract 15 from both sides.

[tex]5x + 15 - 15 < 0 - 15[/tex] [tex]5x < -15[/tex]  

Step 2: Divide both sides by 5.

[tex]\frac{5x}{5} <\frac{-15}{5}[/tex] [tex]x < -3[/tex]

2. Now that we know x < -3, let's graph it!

Since it's less than, we make the number line point to the left, and we make the circle open.

If (-2,11) and (9,22) are two
anchor points on the trend line,
then find the equation of the line.
y = [ ? ]x + [

Answers

Answer:

The equation of the line is- y = x + 13

Please help me its due tommorow

Answers

Answer:

read below for answers

Step-by-step explanation:

7. 4d + 6 =42

d = 9

8. -3y + 12 = -48

y = 20

9. k/2 + 9 = 30

k = 42

10. g/3 - 7 = 15

g = 66

11. z/5 + 3 = -35

z = -190

12. -9h - 15 = 93

h = -12

13. -3(n + 5) = 12

n = -9

14. -17 + b/8 = 13

b = -32

15. 7( c- 12 ) = -21

c = 9

16. -3 + p/7 = -5

p = -14

17. 46 = -6t - 8

t = -9

Write as a single fraction in its simplest form.

Answers

[tex]\dfrac{4}{3x-5} + \dfrac{x+2}{x-1}\\\\\\=\dfrac{4(x-1) + (x+2)(3x-5)}{(3x-5)(x-1)}\\\\\\=\dfrac{4x-4 + 3x^2 -5x +6x -10}{(3x-5)(x-1)}\\\\\\=\dfrac{3x^2 +5x-14}{(3x-5)(x-1)}[/tex]

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