Graphing Inequalities in Two Variables Worksheet

**Page 2**

11.

Determine whether the ordered pair (5, 20) is a solution of the inequality $y$ < $x$^{2} + $x$ - 10.

a. | Yes | ||

b. | No |

[Write original inequality.]

20 < 5

[Substitute 5 for

20 < 25 + 5 - 10

[Evaluate the exponent.]

20 < 20

[Simplify.]

20 is not less than 20.

The ordered pair (5, 20) is not a solution to the inequality

Correct answer : (2)

12.

David can afford to buy 15 mangoes and 20 oranges. He wants at least 10 mangoes and at least 10 oranges. If $x$ represent the number of mangoes ,$y$ represent the number of oranges that David buy , then which of the following systems of inequalities models this situation?

a. | $x$ ≥ 15, $y$ ≥20, $x$ ≥ 10, $y$ ≥ 10 | ||

b. | $x$ ≤ 15, $y$ ≥20, $x$ ≥ 10, $y$ ≥ 10 | ||

c. | $x$ ≤ 15, $y$ ≤20, $x$ ≥ 10, $y$ ≤ 10 | ||

d. | $x$ ≤ 15, $y$ ≤ 20, $x$ ≥ 10, $y$ ≥ 10 |

The maximum number of mangoes that can be bought is 15. So

The maximum number of oranges that can be bought is 20. So

The minimum number of mangoes to be bought is 10. So

The minimum number of oranges to be bought is 10. So

So, the system of inequalities that models the given situation is:

Correct answer : (4)

13.

If the cost of a tape is $10 and the cost of a CD is $12, then write the objective function for the cost of $x$ tapes and $y$ CDs .

a. | C = 12$x$ + 10$y$ | ||

b. | C = 22 + $x$ + $y$ | ||

c. | C = 10$x$ + 12$y$ | ||

d. | C = 120$\mathrm{xy}$ |

The cost C of

Correct answer : (3)