Use a matrix to solve the system:
Answer:
(2.83 , 1 , 4)
Step-by-step explanation:
[tex]2x+2y-z=4\\4x-2y-2z=2\\3x+3y-4z=-4\\[/tex]
Rewrite these equations in matrix form
[tex]\left[\begin{array}{ccc}2&2&-1\\4&-2&-2\\3&3&-4\end{array}\right] \left[\begin{array}{ccc}x\\y\\z\end{array}\right]=\left[\begin{array}{ccc}4\\2\\-4\end{array}\right] \\[/tex]
we can write it like this,
[tex]AX=B\\X=A^{-1}B[/tex]
so to solve it we need to take the inverse of the 3 x 3 matrix A then multiply it by B.
We get the inverse of matrix A,
[tex]A^{-1}=\left[\begin{array}{ccc}7/15&1/6&-1/5\\1/3&-1/6&0\\3/5&0&-2/5\end{array}\right] \\[/tex]
now multiply the matrix with B
[tex]X=A^{-1}B\\\\\left[\begin{array}{ccc}x\\y\\z\end{array}\right] =\left[\begin{array}{ccc}7/15&1/6&-1/5\\1/3&-1/6&0\\3/5&0&-2/5\end{array}\right]\left[\begin{array}{ccc}4\\2\\-4\end{array}\right] \\\\\\\left[\begin{array}{ccc}x\\y\\z\end{array}\right] =\left[\begin{array}{ccc}2.83\\1\\4\end{array}\right] \\[/tex]
Students in an introductory college economics class were asked how many credits they had earned in college, and how certain they were about their choice of major. Their replies are summarized below.
Degree of Certainty
credits earned very uncertain Somewhat Certain very certain Row tot
under 10 24 16 6 46
10 through 59 16 8 20 44
60 or more 2 14 22 38
col total 42 38 48 128
Under the assumption of independence, the expected frequency in the upper left cell is:__________.
A. 2.47
B. 14.56
C. 2.00
D. 11.09
This question is incomplete, the complete question is;
Students in an introductory college economics class were asked how many credits they had earned in college, and how certain they were about their choice of major. Their replies are summarized below.
credits earned very deg.of certainty very Row Total
uncertain somewhat certain certain
under10 24 16 6 46
10 through 59 16 8 20 44
60 or more 2 14 22 38
col total 42 38 48 128
Under the assumption of independence, the expected frequency in the upper left cell is:__________.
A. 12.47
B. 14.56
C. 2.00
D. 11.09
Answer:
Under the assumption of independence, the expected frequency in the upper left cell is 12.47
Option A) 12.47 is the correct Option
Step-by-step explanation:
Given the data in table in the question;
the expected frequency in the upper left cell will be;
Eij = (Ti × Tj) / N
Row total Ti = 38
Column total Tj = 42
Total frequency N = 128
so we substitute
Eij = (38 × 42) / 128
= 1596 / 128
= 12.468 ≈ 12.47
Therefore Under the assumption of independence, the expected frequency in the upper left cell is 12.47
Option A) 12.47 is the correct Option
Find the value of this expression if x = 5 and x=2
xy^2 / -3
Answer:
-20/3
Step-by-step explanation:
here x=5 and y=2 then put the value and get answer.
HEYYYYYYYYYYY YALLLLLLLLLLLLLLLL ADDDDDDDDD MEHHHHHHHHHHHHHHHHH
Answer:
I think the answer is D
Step-by-step explanation:
Find the output g when the input r is 4
g=25-3r
g=?
Answer:
G=13. On kahn
Step-by-step explanation:
Best answer gets brainliest. How do I find X?
Answer:
x=10
Step-by-step explanation:
add al the numbers that are alike so xes with xes blah blah
17x+10=180
-10 both sides
17x=170
divide 17 both sides
check
5(10)=50-1=49
80+5=85
40+6=46
49+85+46=180
Jill paid a sales tax of $1.40 when she bought a vest.What was the price of the vest not including the tax?
Answer:
Price of tne Vest + $40 - 1.40 = $38.6
Step-by-step explanation:
3.5% * n = $1.40
0.035 * n = $1.40
0.035/0.035 * n = $1.40/0.035
n = $40
The price of the vest not including the tax is, $40
What is mean by Percentage?
A number or ratio that can be expressed as a fraction of 100 or a relative value indicating hundredth part of any quantity is called percentage.
Since, Tax is a sum levied by the government or an agency of the government on goods and services. taxes increases the price of products
Now,
Let p = price of a vest
Hence, from the question, this equation can be formed,
⇒ 35% of p = $1.40
⇒ 0.035 x p = $1.4
divide both sides of the equation by 0.035;
⇒ p = $40
Thus, The price of the vest not including the tax is, $40
Learn more about the percent visit:
https://brainly.com/question/24877689
#SPJ2
Complete question is this;
Jill paid a sales tax of $1.40 when she bought a vest. What was price of vest not including tax? Sales tax = 3.5%
Explain how to use the unit-factor method to convert 120 pounds to kilograms.
Answer:
Step-by-step explanation:
lets remember that 1kg=2.2 lb
if
2.2 lbs................................1 kg
120lbs...................................? kg
120/2.2=54.54 kg
Evaluate the expression if y=6 : 30 - 24 ÷ y
Answer:
The answer is 1
Step-by-step explanation:
30 minus 24 is 6 and 6 divided by 6 is 1
A music store marks up the instruments it sells by 30%.
If the price tag on a trumpet says $104, how much did the store pay for it?
A. $ 58.50
B. $ 80
C. No, it did not mark up 30%.
Step-by-step explanation:Since,
A. We have,
Mark up percentage = 30%
Actual price = $ 45,
B. We have,
SP = $ 104,
C. We have,
AP = $ 75,
SP = $100,
Thus, mark up percentage =
= 33.33 %
Hence, store did not mark up the price by 30%.
Which of the symbol correctly relates The two numbers below 19?20
Answer:
<
Step-by-step explanation:
"find the length indicated"
Answer:
huh??
Step-by-step explanation:
y=-|x+3| domain and range
Answer:
the domain is that x is a set of real numbers.
the range is y ≤ -3
Step-by-step explanation:
y = -|x + 3|
y is either positive or equal to zero.
Now, x is all real numbers because any value of x used will yield a valid value of y.
Thus, we can say that the domain is that x is a set of real numbers.
Now, for the range:
The minus sign in front of the absolute value indicates that the function has a maximum value.
Thus, the range is y ≤ -3
I gave extra points and I will give brainliest
Which of these is an example of a random sample?
A. Mrs. Baker selects the 10 students who raised their hands to volunteer to fill out a survey.
B. Mrs. Baker selects the 10 students whose names are drawn from a bag to fill out a survey.
C. Mrs. Baker selects the 10 students who arrived to class first on Monday to fill out a survey.
D. Mrs. Baker selects the 10 students with the highest grade point averages to fill out a survey.
Answer:
I think it's A.
Step-by-step explanation:
I hope it is helpful to you
At Tim’s party 4 people are sharing 2/3 of a pizza. How much will each guest get
Answer:
Each person would get 1/6 of the pizza
Step-by-step explanation:
1/3 divided by 2 is 1/6. Do that again and you will get four of 1/6.
Solve the system of equations y=x^2-3x+2
y=-9x-3
How many solutions does this system of equations have?
Answer:
I believe the answer is '2 solutions'.
Step-by-step explanation:
Combine each equation, solve the resulting question which comes out as two seperate variables, x = -1.197-- and y = 7.3990. I believe your answer is '2 solutions' because of this.
Answer:
1 solution
Step-by-step explanation:
what is the answer to (x+3)^5
(x + 3)⁵
= x⁵ + 3⁵
= x⁵ + 243
please help me!!!!!!! asap
5/8 didved by 1/4 plz help me with this
Answer:
The answer is 2.5 or 5/2 as a fraction.
Step-by-step explanation:
P.S Can I have brainliest?
Answer:
2.5
Step-by-step explanation:
[tex]\frac{5}{8}[/tex] ÷ [tex]\frac{1}{4}[/tex]
turns into
[tex]\frac{5}{8}[/tex] ×[tex]\frac{4}{1}[/tex] = [tex]\frac{20}{8}[/tex]
and 20/8 as a decimal is 2.5 :) hope this helps!
grab the image of the rectangle DEFG reflection across the line x= 3
Answers:
D ' at (9, -9)E ' at (5, -9)F ' at (5, -2)G ' at (9, -2)Refer to the diagram below
========================================
Explanation:
For points D,E,F,G we will follow these steps
Shift everything 3 units to the left so that the vertical line x = 3 will move on top of the y axis (which is the vertical line x = 0).Reflect across the y axis using the rule [tex](x,y) \to (-x,y)[/tex]. Here we have the x coordinate flip in sign from positive to negative, or vice versa. The y coordinate stays the same.Shift everything 3 units to the right so we effectively undo the first step. This places the points in the proper final position.Let's go through an example:
Point D is located at (-3, -9). Apply the three steps mentioned above.
Shift point D three units to the left to arrive at (-6, -9)Reflect over the y axis to go from (-6, -9) to (6, -9)Lastly, shift 3 units to the right to move to (9, -9) which is the location of D'In short, D(-3,-9) reflects over the line x = 3 to land on D ' (9, -9)
The other points E, F, G will follow the same steps to get the answers you see at the top.
The diagram below visually summarizes everything.
-------------
Side notes:
The distance from D to the line of reflection is the same as the distance from D' to the line of reflection. Put another way, the line of reflection bisects segment DD'. Points E,F,G follow the same property.Going from D to E to F to G has us go counterclockwise. Going from D' to E' to F' to G' has us go clockwise. Any reflection transformation will flip the orientation.Which statement can you conclude is true from the given information?
Answer:
angle IJA is a right angle
The data below gives the mean price (in cents) of a liter of regular gasoline at self-service filling stations at a sample of six urban centers in Canada in May 2011.
Urban area Price/liter
St. John, NL 137.1
Halifax 133.6
Montreal 136.2
Regina 132.3
Saskatoon 132.2
Yellowknife 138.9
Required:
a. Find the sample mean (in cents).
b. Find the sample standard deviation (in cents).
c. Find a 90% confidence interval for the mean gasoline price per liter across urban Canada in May 2011. Provide the lower and upper limits for your confidence interval.
d. Find a 95% confidence interval for the mean gasoline price per liter across urban Canada in May 2011. Provide the lower and upper limits for your confidence interval.
Answer:
135.05 ; 2.762 ; (133.201, 136.899) ; (132.840, 137.260)
Step-by-step explanation:
Given the data:
Urban area Price/liter
St. John, NL 137.1
Halifax 133.6
Montreal 136.2
Regina 132.3
Saskatoon 132.2
Yellowknife 138.9
Mean = (137.1 + 133.6 + 136.2 + 132.3 + 132.2 + 138.9) / 6
= 810.3 / 6
= 135.05
Standard deviation (σ) : √Σ(X - mean)²/n-1
(137.1 - 135.05)^2 + (133.6 - 135.05)^2 + (136.2 - 135.05)^2 + (132.3 - 135.05)^2 + (132.2 - 135.05)^2+ (138.9 - 135.05)^2 = 38.135
√(38.135 / (6 - 1))
= √7.627
= 2.7617023
= 2.762
C.)
90% confidence interval of the mean :
Mean ± Zcrit * σ/√n
Zcrit at 90% = 1.64
135.05 ± 1.64 * (2.762/√6)
135.05 ± 1.64 * 1.1275817
Lower Value = (135.05 - (1.64 * 1.1275817)) = 133.201
Upper Value = (135.05 + (1.64 * 1.1275817))) = 136.899
Confidence interval = (133.201, 136.899)
D.)
95% confidence interval of the mean :
Mean ± Zcrit * σ/√n
Zcrit at 95% = 1.96
135.05 ± 1.96 * (2.762/6)
135.05 ± 1.96 * 1.1275817
Lower Value = (135.05 - (1.96 * 1.1275817)) = 132.840
Upper Value = (135.05 + (1.96 * 1.1275817)) = 137.260
Confidence interval = (132.840, 137.260)
PLEASE HELP!! It’s urgent!! I will mark brainliest
Answer:
a,c,d
Step-by-step explanation:
Answer:
the answer is F, C, A
4x4xy+6/3
Please i will give brainliest
GIVE ME THE ANSWER!!!!!!!!!!!!!!!!!!
Find sin(theta) , if cos(theta)=(4/9) and tan(theta) < 0
Recall that
cos²(x) + sin²(x) = 1
for all x, so that
sin(x) = ± √(1 - cos²(x))
Given that cos(θ) = 4/9 > 0, and
tan(θ) = sin(θ) / cos(θ) < 0
it follows that sin(θ) < 0, so
sin(θ) = - √(1 - cos²(θ)) = - √(1 - (4/9)²) = - √(65)/9
The value of sinθ is √(65)/9.
What is a sine function?The sine function in trigonometry is the ratio of the hypotenuse's length to the opposite side's length in a right-angled triangle. To determine a right triangle's unknown angle or sides, utilize the sine function.
Since cos(theta) = 4/9 and tan(theta) < 0, we know that theta is in the second quadrant of the unit circle, where cosine is positive and sine is positive.
We can use the Pythagorean identity to find sin(theta):
sin²(theta) + cos²(theta) = 1
Substituting in the given value of cos(theta), we get:
sin²(theta) + (4/9)² = 1
sin²(theta) + 16/81 = 1
sin²(theta) = 1 - 16/81
sin²(theta) = 65/81
Taking the square root of both sides, we get:
sin(theta) = ± sqrt(65)/9
Since theta is in the second quadrant where sine is positive, we can take the positive root:
sin(theta) = sqrt(65)/9
Therefore, sin(theta) = sqrt(65)/9.
To learn more about the sine function;
https://brainly.com/question/12015707
#SPJ2
Kenia rotated Triangle ABC 90° counterclockwise to create Triangle A’B’C’. If Kenia performed this transformation correctly, what is the measure of angle B'? What is the measure of angle A and C. Number value only. URGENT
Answer:
B' = 105°
C = 27°
A = 48°
Step-by-step explanation:
Given
B = 105°
C = (2x - 3)°
C' = (5x - 48)°
Rotation = 90°
Before solving the requirements of this question, it should be noted that rotation do not change the angle of shapes.
i.e. an angle retain its measurements pre and after rotation.
Solving (a): The measurement of B'
Using the analysis above.
B' = B
Recall that
B = 105°
So:
B' = 105°
Solving (b): A and C
First, I'll solve for C.
Using the same analysis above.
C = C'
Substitute values for C and C'
5x - 48 = 2x - 3
Collect like terms
5x - 2x = 48 - 3
3x = 45
Multiply both sides by ⅓
⅓*3x = ⅓*45
x = 15
Substitute 15 for x in
C = (2x - 3)°
C = 2 * 15 - 3
C = 30 - 3
C = 27°
Solving for A
The sum of angles (A, B and C) is represented as:
A + B + C = 180
Substitute values for B and C
A + 105° + 27° = 180°
A + 132° = 180°
Collect like terms
A = 180° - 132°
A = 48°
What is the quotient of 28 divided by 7 increased by 4
Answer:
8 beacaus the seven increased from 4
The quotient after increased by 4 is 8.
To calculate the quotient of 28 divided by 7, we perform the division and get:
28 ÷ 7
= 28/7
= (7 x 4)/ 7
= 4
Next, we are asked to increase this quotient by 4. Adding 4 to the quotient:
= 4 + 4
= 8.
Therefore, the quotient after increased by 4 is 8.
Learn more about Division here:
https://brainly.com/question/2273245
#SPJ6
Verify sin4x-sin²x=cos4x-cos²x is an identity.
the 4 is supposed to be small like the 2
Answer:
It's an identityStep-by-step explanation:
[tex]\sin^4x-\sin^2x=\cos^4x-\cos^2x\\\\Ls=\sin^2x(\sin^2x-1)=-\sin^2x(1-\sin^2x)=-\sin^2x\cos^2x\\\\Rs=\cos^2x(\cos^2x-1)=-\cos^2x(1-\cos^2x)=-\cos^2x\sin^2x\\\\Ls=Rs\\\\\text{used}\\\\a^n\cdot a^m=a^{n+m}\\\\\text{distributive property}\ a(b+c)=ab+ac\\\\\sin^2x+\cos^2x=1\to \sin^2x=1-\cos^2x\\\\\sin^2x+\cos^2x=1\to \cos^2x=1-\sin^2x}[/tex]
Which shows the best use of the associative and commutative properties to
make simplifying 2.4 + 13 – 5 + 3.6 +7 easier?
O A. (2.4 + 13) + (-5 +3.6 + 7)
O B. (2.4 + (-5) + 13) + (7 + 3.6)
Oc. (7+ 2.4 + 13) + [3.6+ (-5)]
O D. (2.4+ 3.6) + [13 +7+(-5)]
SUBMIT
Answer: D
Step-by-step explanation:
The best use of the associative and commutative properties to simplify the expression 2.4 + 13 - 5 + 3.6 + 7 would be:
D. (2.4 + 3.6) + [13 + 7 + (-5)]
By applying the associative property, we can group the numbers in a way that allows for easier computation.
Here, we group 2.4 and 3.6 together and 13, 7, and -5 together. This allows us to simplify each group separately and then add the results together.
Calculating the groups:
(2.4 + 3.6) = 6
[13 + 7 + (-5)] = 15
Now, we add the results together:
6 + 15 = 21
So, the simplified expression is 21. Therefore, option D provides the best use of the associative and commutative properties to simplify the given expression.
Learn more about the associative and commutative properties here:
https://brainly.com/question/29279825
#SPJ2