Answer: D
Step-by-step explanation:
Consider the first equation. Subtract 3x from both sides.
y−3x=−2
Consider the second equation. Subtract x from both sides.
y−2−x=0
Add 2 to both sides. Anything plus zero gives itself.
y−x=2
To solve a pair of equations using substitution, first solve one of the equations for one of the variables. Then substitute the result for that variable in the other equation.
y−3x=−2,y−x=2
Choose one of the equations and solve it for y by isolating y on the left hand side of the equal sign.
y−3x=−2
Add 3x to both sides of the equation.
y=3x−2
Substitute 3x−2 for y in the other equation, y−x=2.
3x−2−x=2
Add 3x to −x.
2x−2=2
Add 2 to both sides of the equation.
2x=4
Divide both sides by 2.
x=2
Substitute 2 for x in y=3x−2. Because the resulting equation contains only one variable, you can solve for y directly.
y=3×2−2
Multiply 3 times 2.
y=6−2
Add −2 to 6.
y=4
The system is now solved.
y=4,x=2
Answer: x = -4 ; Angle = 60°
Concept:
The given figure is a triangle with 3 arc signs on each angle. This <u>arc sign </u>stands for the corresponding angles are congruent, which in this question, it shows that all three angles are congruent. Sometimes, if the figure has multiple angles and there are different groupings of congruent angles, then we use different numbers of arcs or symbols.
Solve:
<u>Given information</u>
An angle = 3x + 72
Total measure of angles = 180 (triangle angle sum theorem)
Total number of congruent angles = 3
<u>Given expression</u>
Total measure = Total number of congruent angles × An angle measure
<u>Substitute values into the expression</u>
180 = 3 (3x + 72)
<u>Divide 3 on both sides</u>
180 / 3 = 3 (3x + 72) / 3
60 = 3x + 72
<u>Subtract 72 on both sides</u>
60 - 72 = 3x + 72 - 72
-12 = 3x
<u>Divide 3 on both sides</u>
-12 / 3 = 3x / 3

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<u>Find the angle measure</u>
3x + 72 = 3 (-4) + 72 = 
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Answer:
x = 3
Step-by-step explanation:
2x - y = 4
y = -2x + 8
-y = -2x + 4
y = -2x + 8
0 = -4x + 12
-4x = -12
x = 3
Answer:
The 90% confidence interval is 0.575 to 0.625.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of
, and a confidence interval
, we have the following confidence interval of proportions.

In which
Z is the zscore that has a pvalue of
.
For this problem, we have that:

90% confidence interval
So
, z is the value of Z that has a pvalue of
, so
.
The lower limit of this interval is:

The upper limit of this interval is:

The 90% confidence interval is 0.575 to 0.625.