Exercise 13 Page 85

To solve the equation we need to isolate q on one side of the equation. By subtracting 13 from both sides, we can cancel it from the right-hand side.

4=q+13

SubEqn

LHS-13=RHS-13

4-13=q+13-13

SubTerm

Subtract term

-9=q

RearrangeEqn

Rearrange equation

q=-9

Therefore, q=-9 is the solution to the equation. To check that we have the correct solution, we can substitute q=-9 into the original equation and simplify.

4=q+13

Substitute

q= -9

4? = -9+13

CommutativePropAdd

Commutative Property of Addition

4? =13+(-9)

AddNeg

a+(- b)=a-b

4? =13-9

SubTerms

Subtract terms

4=4

Since the left-hand side and right-hand side are equal, q=-9 is a correct solution.