I need help with this problem
Solve the following system of equations using elimination by multiplication.
Answers
If the given equations are indeed
[tex]\begin{cases}x-\frac4{5y} = 9\frac45 \\ -14x - 4y = -46\end{cases}[/tex]
we can solve by substitution. Solve the second equation for x :
[tex]-14x - 4y = -46[/tex]
[tex]\implies 7x + 2y = 23[/tex]
[tex]\implies7x = 23 - 2y[/tex]
[tex]\implies x = (23 - 2y)/7[/tex]
Substitute this into the first equation and solve for y :
[tex]\dfrac{23-2y}7 - \dfrac4{5y} = 9\dfrac45[/tex]
On the right side, write the mixed number as an improper fraction:
[tex]9 + \dfrac45 = \dfrac{45}5 + \dfrac45 = \dfrac{45+4}5 = \dfrac{49}5[/tex]
[tex]\implies \dfrac{23-2y}7 - \dfrac4{5y} = \dfrac{49}5[/tex]
Multiply both sides of this equation by 35y (the LCM of the denominator of all three fractions)
[tex]35y \times \dfrac{23-2y}7 - 35y \times \dfrac4{5y} = 35y \times \dfrac{49}5[/tex]
[tex]5y\times(23-2y) - 7\times4 = 7y \times 49[/tex]
[tex]115y - 10y^2 - 28 = 343y[/tex]
[tex]10y^2 + 228y + 28 = 0[/tex]
[tex]5y^2 + 114y + 14 = 0[/tex]
To solve the quadratic, I'll complete the square :
[tex]5\left(y^2 + \dfrac{114}5y\right) + 14 = 0[/tex]
[tex]5\left(\left(y + \dfrac{57}5\right)^2 - \left(\dfrac{57}5\right)^2 \right) + 14 = 0[/tex]
[tex]5\left(y + \dfrac{57}5\right)^2 - \dfrac{57^2}5 + 14 = 0[/tex]
[tex]5\left(y + \dfrac{57}5\right)^2 = -\dfrac{3179}5[/tex]
This system has no real solutions since the square of any real number must be positive.
If we allow complex numbers, we can continue solving to end up with two complex solutions for y,
[tex]\left(y + \dfrac{57}5\right)^2 = -\dfrac{3179}{25}[/tex]
[tex]y + \dfrac{57}5 = \pm i \sqrt{\dfrac{3179}{25}}[/tex]
[tex]y = -\dfrac{57}5 \pm i\dfrac{17\sqrt{11}}5[/tex]
and we can go on to solve for x.
Hence my comment; I suspect you meant to write the system
[tex]\begin{cases}x-\frac45 y = 9\frac45 \\ -14x - 4y = -46\end{cases}[/tex]
because its solution is far simpler. Multiplying through the first equation by 5 gives
[tex]5\times x - 5 \times \dfrac45 y = 5 \times 9\dfrac45[/tex]
[tex]\implies 5x - 4y = 49[/tex]
(since we know 9 + 4/5 = 49/5)
Meanwhile, multiplying through the second equation by -1 gives
[tex]-1 \times (-14x) + (-1) \times (-4y) = -1 \times (-46)[/tex]
[tex]\implies 14x + 4y = 46[/tex]
So if we combine the two equations, we can eliminate y and solve for x :
[tex](5x - 4y) + (14x + 4y) = 49 + 46[/tex]
[tex]\implies 19x = 95[/tex]
[tex]\implies \boxed{x = 5}[/tex]
and solving for y gives
[tex]14x + 4y = 46[/tex]
[tex]\implies 70 + 4y = 46[/tex]
[tex]\implies 4y = -24[/tex]
[tex]\implies \boxed{y = -6}[/tex]
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To reach the roof , how far away from the building should he place the base of the ladder ?
Answers
Answer: many be 5-10 feet
Sean is travelling. He has a flight of 2 hours 30 minutes, a stopover of 45 minutes and then another flight of 4.75 hours. What is his total travel time? Give your answer in hours and minutes.
Answers
Answer:
52 hours and 25 min
Step-by-step explanation:
2 1/2+45+4.75= 52.25
what is factor write its type
Answers
Answer:
These are the answers
Step-by-step explanation:
factor, in mathematics, a number or algebraic expression that divides another number or expression evenly—i.e., with no remainder. For example, 3 and 6 are factors of 12 because 12 ÷ 3 = 4 exactly and 12 ÷ 6 = 2 exactly. The other factors of 12 are 1, 2, 4, and 12.
Hope it helps !
The price of an item has been reduced by 45%. The original price was $60. What is the price of the item now?
Answers
Answer:
the answer to the question is 15$
One serving of ice cream has 320 calories. If there are 6 servings in the container and you ate of the container, how many calories did you eat?
Answers
Answer: You ate 1920 calories
Step-by-step explanation:
It’s pretty simple,
all you have to do is multiply 6 by 320.
this then gets you 1920
Answer:
1920 calories
Step-by-step explanation:
6servings*320cal/servings = 1920cal (servings cancel)
7.9 is what percent of 8? Round to the nearest tenth.
Answers
Answer:
98.75
Step-by-step explanation:
have a nice day
The answer is 100 percent.
Answer two questions
25 points
Answers
Answer:
1) -2x - 3
2) -2a - 2
Step-by-step explanation:
Problem 1
To solve this problem, we only have to combine like terms. What are the like terms in this problem? Well, we have two x-terms (-10x and 8x) and two integers, or constants (1 and -4). So, let's rearrange the expression and then combine those terms.
-10x + 8x + 1 - 4
-2x - 3
Problem 2
This expression is a little more complicated since we have to distribute a 2 onto the two terms in the parentheses.
2(1 - a) - 4
2(1) - 2(a) - 4
2 - 2a - 4
Next, we can combine like terms.
-2a + 2 - 4
-2a - 2
[tex]\huge\textbf{Hey there!}[/tex]
[tex]\huge\text{Number 1}[/tex]
[tex]\large\textsf{-10x + 1 + 8x - 4}\\\large\text{COMBINE the LIKE TERMS}\\\large\textsf{= (-10x + 8x) + (1 - 4)}\\\large\textsf{= -2x - 3}\\\\\huge\text{Therefore, your answer is: \boxed{\mathsf{-2x - 3}}}\huge\checkmark[/tex]
[tex]\huge\text{Number 2}[/tex]
[tex]\large\textsf{2(1 - a) - 4}\\\large\text{DISTRIBUTE 2 WITHIN the PARENTHESES}\\\large\textsf{= 2(1) + 2(-a) - 4}\\\large\textsf{= 2 - 2a - 4}\\\large\text{COMBINE the LIKE TERMS}\\\large\textsf{= (-2a) + (2 - 4)}\\\large\textsf{= -2a - 2}\\\\\\\huge\text{Therefore, your answer is: \boxed{\mathsf{-2a - 2}}}\huge\checkmark[/tex]
[tex]\huge\textbf{Good luck on your assignment \&}\\\huge\textbf{enjoy your day!}[/tex]
~[tex]\frak{Amphitrite1040:)}[/tex]quick pls!! my math grade is at a B! I need to raise it.
Answers
the diagram shows 3 identical circles inside a rectangle. each circle touches the other two circles and the sides of the rectangle, as shown in the diagram. the radius of each circle is 32mm. work out the area of the rectangle. give your answer correct to 3 significant figures.
Answers
Answer:
2640mm
Step-by-step explanation:
I'm assuming you need the area of the rectangle which the circles don't take up.
First, to find the area of the whole rectangle:
length x width
to find length:
the length is 1 circle, therefore it is the diameter of the circle, which is 32 x 2 = 64mm
to find width:
the width is 3 circles, which is the radius 6 times, so 32 x 6 = 192mm
So, area of rectangle = 64 x 192 = 12288mm
Now to find the area the circles take up:
area of 1 circle =
[tex]\pi \times {r}^{2} [/tex]
=
[tex]\pi \times {32}^{2} [/tex]
=
[tex]1024\pi[/tex]
As we have 3 circles, we multiply this by 3:
[tex]1024\pi \times 3 = 3072\pi[/tex]
Finally we subtract the area of the three circles from the area of the rectangle:
[tex]12288mm - 3072\pi = 2637[/tex]
As we need to round it to 3 significant figures, the answer is 2640mm
Find the measure of the angle x to the nearest tenth. Question 7 options: 33. 5° 56. 5° 28. 9° 44. 3°.
Answers
The question is an illustration of right-angled triangles
The approximated value of x is 33.5 degrees
The given parameters are:
[tex]\theta = x[/tex]
[tex]Hypotenuse = 58[/tex]
[tex]Opposite = 32[/tex]
To determine the measure of angle x, we simply make use of the following sine ratio.
[tex]\sin(\theta) = \frac{Opposite}{Hypotenuse}[/tex]
So, we have:
[tex]\sin(x) = \frac{32}{58}[/tex]
[tex]\sin(x) = 0.5517[/tex]
Take arc sine of both sides
[tex]x = \sin^{-1}(0.5517)[/tex]
This gives
[tex]x = 33.5[/tex]
Hence, the approximated value of x is 33.5 degrees
Read more about right-angled triangles at:
https://brainly.com/question/16195823
please help me, tysmm! and no spam or links please it's rlly annoying -_-
Answers
Rise/Run.
Down 2/ Left 1. Because it’s going down, put a negative.
original price: $24.50
discount:30%
tax:2%
Answers
Answer -
Discount -
24.50 x 30/100
24.5 x 0.3 = 7.35 saved
24.5 - 7.35 = 17.15
Discount you saved $7.35 , which brings you price 17.15
tax -
17.15 + 0.34 = 17.49
With taxes you pay 17.49
HOPE THIS HELPS :)
if you multiply a number by 3 an then subtract 5,you will get 40.what is the number?
Answers
Answer:
The answer is 15
Step-by-step explanation:
15*3=45-5=40
what is 7/8 x 4 ? ( 7/8 is a fraction)
Answers
Answer:
7/2 or 3 1/2
Step-by-step explanation:
7/8*4/1=28/8
Simplify= 7/2 or as a mixed fraction = 3 1/2
Hope this helps
Can I have the brainliest if I am right?
How many real roots does the quadratic function h (x) = 2x2 – 3x + 6 have?
Answers
±
i
√
39
4
I hope this helps
What is -10 5/6 times 8 1/2
Answers
Answer:
92 1/12
Step by step explanation:
92 1/12
Step by step
The coefficient of 3x is "3."
True
False
Answers
Answer:
true
Step-by-step explanation:
Answer:
false.
Step-by-step explanation:
btw i love your pfp.
The formula for electrical energy, P, is P = I2R, where I is current and R is resistance. The formula for I in terms of P and R is ....
Answers
Answer:
[tex]i = \sqrt{ \frac{p}{r} } [/tex]
PLEASE HELP AS SOON AS POSSIBLE I NEED TO SUBMIT THIS IN 10 MINUTES!!!!
IT GIVES 20 points!!!
Answers
Answer:
1. A. falling asleep
2. D. taking more time to wind down before bedtime
3. B. There is more than one reason that people have trouble sleeping.
4. C. The problem of falling asleep has been around for a long time and affects many people
5. A. why kids have trouble falling asleep and what they can do about it
6. A. something done over and over
Step-by-step explanation:
Please HELP!!!
What are the first 4 terms of the arithmetic sequence in the graph?
Enter your answers in the boxes.
_,_,_, and _
Answers
Answer:
- 3, 1, 5, 9
Step-by-step explanation:
The first 4 terms are the values of y corresponding to x = 1, 2, 3, 4 , that is
(1, - 3 ) , (2, 1 ) , (3, 5 ) , (4, 9 )
first 4 terms are - 3, 1, 5, 9
Which expression is equivalent to (15aºb²c34) (3a166-29cº) for all values of a, b, and
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Answers
The answer is 45a16c34b27
Shivani had 3/10 of a pound of blueberries. Shivani let her friend Rosa eat 1/4 of the
blueberries. How many pounds of blueberries did Rosa eat?
Write your answer as a fraction or as a whole or mixed number.
a
pounds
Answers
Can you prove that 4+2=5+1 is true without solving both sides of equation?
Answers
Answer:
Here you go...
Step-by-step explanation:
You have 4, and you have 5.
You have 4+2 and you have 5+1
So, you take a 1 from the 2 in the first problem, which gives u 4+1 that equals 5.
Therefore, if u put the first equation in a simpler form then you get 5+1 with the other equation. So it would look like 5+1=5+1.
FURTHERMORE, 4+2= 5+1 (because you simplify 2 into a 1).
So. 5+1 equals 5+1. (which is common sense... 5+1= 6.)
Need help on geometry TO PASS My Class so can you help please
Answers
Answer:
x=12
Step-by-step explanation:
since it is an equilateral triangle the angle r all the same the angle have to equal 60
Since it's a equilateral triangle.
[tex]\\ \sf\longmapsto 5x+5x+5x=180[/tex]
[tex]\\ \sf\longmapsto 15x=180[/tex]
[tex]\\ \sf\longmapsto x=12[/tex]
m<S=5x=60°Sonja has a bank account balance of $1400. Each week, her balance changes by-$85.25. She wants to keep the balance above $377. How many weeks will Sonja's balance remain above $377? Select from the drop-down menu to correctly complete the statement. Sonja's balance will remain above $377 Choose... v weeks.
Answers
Answer:
12 Weeks
Step-by-step explanation:
$1400 - $377 = $1023
1023 / 85.25 = 12 Weeks
Answer:
Its will take Sonja 12 weeks
Step-by-step explanation:
Helpppp
Evan spent 20 hours doing homework last week. This week he spent 25 hours doing homework. He says that he spent 125% more time doing homework this week. Is he correct? Show your work to justify your decision.
Answers
Answer: Evan is incorrect
Step-by-step explanation:
20/20 - 25 x 100 =
5/20 x 100/1 =
500/20
500/20 = 20%
Evan would only be correct is he doubled the 20 hours to make it 40 hours
Hope this helps✌
What is the y-value of the vertex of the function f(x)=â’(xâ’3)(x 11)?.
Answers
Answer:
What is the y-value of the vertex of the function f(x)=â’(xâ’3)(x 11) 1060 by cata
PLEASE HELP TEST DUE SOON⚠️ which graph should be used to show the situation described? The temperature increases by4° every hour
Answers
Step-by-step explanation:
the bottom left is the right option.
just by saying "the temperature increases ..." the 2 options on the right are wrong. the line has to go up, not down.
the first graph (top left) increases too strongly, way more than just 4ft per hour.
Graph A (-3.-2), B (-5,-4), and C (-3,-4)
Pls solve the problems
Answers
Graph attached
Group Work 2.6 Newton's Law of Cooling states that an object cools at a rate proportional to the difference between the temperature of the object and the room temperature. The temperature of the object at a time t is given by a function f(t)= alpha x^ prime prime +a where a = mc * pi temperature c = initial difference in temperature between the object and the room r = constant determined by data in the problem Suppose you make yourself a cup of tea. Initially the water has a temperature of 95 degrees * C ; 5 minutes later the tea has cooled to 65 degrees * C Problem: When will the tea reach a drinkable temperature of 40°C? Hint: Assume that the room temperature a = 22 degrees * C . First solve for r and then find tapplying the natural logarithm.
Answers
Answer:
ΔT = ΔT0 e^-K T
As I understand Newton's Law of Cooling
ΔT at any time is the difference between the temperature and the surroundings
Originally ΔT0 = 95 - 22 difference between 95 and room temperature
65 - 22 = 33 = 73 e^-KT where t is time to cool to 65 deg
ln (33/73) = -KT K = .794 / 5 = .159 where 5 is time to cool to 65 deg
40 - 22 = 73 e^-.159 T where t is time to cool to 40 deg
18 = 73 e^-.159 T
ln (18 / 73) = -.159 T
T = 8.8 min
It would take 8.8 min for the object to cool to 40 deg C
Suppose the object cooled from 95 to 90 deg, then
ln 68 / 73 = -.159 T and T = .45 min
Answer:
13.2 minutes
Step-by-step explanation:
We cannot tell what your equation is supposed to be. Usually, the equation will have the form ...
f(t) = c·e^(kt) +r
where c is the initial temperature difference (95 -22 = 73) and r is the room temperature (22). The value of k can be found from the given intermediate temperature and time.
f(5) = 65 = 73·e^(k·5) +22
43/73 = e^(5k)
Taking the natural log gives ...
5k = ln(43/73)
k = ln(43/73)/5 ≈ -0.105852
__
We want to find t for f(t) = 40. Then ...
f(t) = 40 = 73·e^(-0.105852t) +22
18/73 = e^(-0.105852t)
t = ln(18/73)/-0.105852 ≈ 13.227
The tea will be drinkable after 13.2 minutes.
__
In the attached, we have used exponential regression to find the equation of the temperature curve.