Exercise 16 Page 117

To solve the equation, we have to isolate x on one side using inverse operations. To begin with, we want to collect all of the constants on one side of the equation. The inverse operation to subtraction is addition, so to eliminate - 21 we have to add 21 to both sides of the equation. Next, we have to eliminate - 20x from the right-hand side. As before, to eliminate it we will add 20x to both sides of the equation.

- 9x=- 20x-66

AddEqn

LHS+20x=RHS+20x

- 9x + 20x=- 20x-66 + 20x

AddTerms

Add terms

11x=- 66

Finally, we have to eliminate 11 from in front of x. Since multiplication and division are inverse operations, we have to divide by 11.

11x=- 66

DivEqn

.LHS /11.=.RHS /11.

11x/11=- 66/11

CalcQuot

Calculate quotient

x=- 6