Exercise 9 Page 71

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 you divide or multiply by a negative number, you must reverse the inequality sign.

20≥4/5w

MultIneq

LHS* 5/4 ≥ RHS * 5/4

5/4* 20 ≥5/4*4/5w

MultFracByInverse

a/b* b/a=1

5/4* 20 ≥ w

MoveRightFacToNum

a/c* b = a* b/c

5* 20/4 ≥ w

Multiply

Multiply

100/4 ≥ w

CalcQuot

Calculate quotient

25≥ w

RearrangeIneq

Rearrange inequality

w≤25

The above tells us that all values less than or equal to 25 will satisfy the inequality. Below we demonstrate the inequality by graphing the solution set on a number line. Notice that w can equal 25, which we show with a closed circle on the number line.