Exercise 21 Page 396

Inequalities can be solved in the same way as equations, by performing inverse operations on both sides until the variable is isolated. The only difference is that when we divide or multiply by a negative number, we must reverse the inequality sign.

1/11c ≥ 9

MoveRightFacToNum

a/c* b = a* b/c

c/11 ≥ 9

MultIneq

LHS* 11 ≥ RHS * 11

c/11* 11 ≥ 9* 11

CalcQuot

Calculate quotient

c≥ 9* 11

Multiply

Multiply

c ≥ 99

Note that all values of c greater than or equal to 99 satisfy the inequality. Now let’s graph the inequality on a number line. Since c is greater than or equal to 99, we will shade the part of the number line to the right of our point at 99, including 99 with the closed circle.