AnswersAlgebra 2 - Semester 1 PathwaysTwo-Variable Linear Inequalities

Two-Variable Linear Inequalities Answers

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Select all of the following ordered pairs that are solutions to the inequality.

A
(0, 0)
B
(20, 0)
C
(20, 80)
D
(80, 20)
E
(80, 0)
7

Ezra works two summer jobs to save for a laptop that costs at least $1100. He charges $15/hr to mow lawns and $10/hr to walk dogs. Recall the inequality that represents this situation: .Is (60, 20) a solution? How do you know? What does this point represent?

Question illustration
Answer:

Yes, (60, 20) is a solution. When you substitute the values into the inequality, 15(60) + 10(20) ≥ 1100 becomes 900 + 200 ≥ 1100, or 1100 ≥ 1100. Since this is a true statement, the point is a solution. This point represents Ezra working 60 hours mowing lawns and 20 hours walking dogs, which earns him exactly the $1,100 he needs for the laptop.

8

Which of the following did you include in your solution?

A
The coordinate pair (60, 20) is a solution because it satisfies the inequality .
Option A
B
The coordinate pair (60, 20) is a solution because Ezra earns 60 x $15 = $900 mowing lawns and 20 x $10 = $200 walking dogs, for a total of $1100.
C
Ezra can spend 60 hours mowing lawns and 20 hours walking dogs to earn enough money for the laptop.
11

Which of the following did you include in your solution?

A
Graph only the first quadrant since x and y must be nonnegative.
B
The graph has a solid boundary line.
C
Graph the boundary line using the related equation, y = –1.5x + 110.
D
Choose a test point such as (0, 0) to determine which half-plane to shade.
E
If the test point is true, shade that side of the boundary line.
F
Shade to the right of the solid boundary line.
12

=✔ ><=

A
<
B
>=
C
>
D
<=
13

⇒ 1180.

Answer:

60

16

How is the graph of the solution affected?

A
The boundary line becomes dashed.
B
The boundary line changes slope.
C
The boundary line is translated vertically.
D
The shading switches to the other side of the boundary line.
33

Ezra works two summer jobs to save for a laptop that costs at least $1100. He charges $15/hr to mow lawns and $10/hr to walk dogs. He currently charges in half-hour intervals. Recall the inequality that represents this situation: .Ezra decides to charge per dog instead of per hour. How does the solution set change? What are the limitations on x and y? Explain.

Question illustration
Answer:

The solution set changes because the allowed values for y are now whole numbers, as Ezra cannot walk a fraction of a dog. Previously, y represented hours and was restricted to non-negative multiples of 0.5. The limitations on x remain the same: x must be a non-negative multiple of 0.5 because Ezra still charges by the half-hour for mowing lawns. Both variables must be non-negative because he cannot work negative hours or walk a negative number of dogs.

34

Which of the following did you include in your explanation?

A
The limitations on y-values changed from nonnegative multiples of one-half to whole numbers, since Ezra cannot walk a fractional number of dogs.
B
The limitations on x-values did not change and must be nonnegative multiples of one-half, since Ezra cannot work negative hours and charges by the half-hour.
39

Select question ca8c2b4c

A
(2, 1)
B
(3, 0)
C
(4, 1)
46

Ezra works two summer jobs to save for a laptop that costs at least $1100. He decides to adjust his rates to $250 per lawn (x) for the summer and $300 per dog (y) for the summer, and to limit himself to 2 dogs.Describe how to find a solution graphically.

Answer:

First, write the inequality 250x + 300y ≥ 1100 and graph the boundary line in the first quadrant, since the number of lawns and dogs must be non-negative. Because the laptop costs at least $1100, shade the half-plane above the line (the side that does not include the origin). Then, draw a horizontal line at y = 2 to represent the limit of 2 dogs. The solutions are the points with integer coordinates that fall within the intersection of the shaded region and the area on or below the line y = 2.

47

Which of the following did you include in your answer?

A
Graph in the first quadrant because x and y are nonnegative.
B
Determine and graph the inequality that represents the situation .
Option B
C
Shade the half-plane that does not include the origin since (0, 0) does not satisfy the inequality.
D
Draw a horizontal line at y = 2 for 2 dogs.
E
Solutions lie on or below the part of the horizontal line that is in the shaded region.

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