Exercise 1 Page 47

We need to isolate x on one side to solve the equation. To do this, we will use the Addition Property of Equality to gather all the constant terms on the right-hand side of the equation and then simplify.

x-7=15

AddEqn

LHS+7=RHS+7

x-7+7=15+7

AddTerms

Add terms

x=22

We will check our solution by substituting this result back into the original equation and simplifying.

x-7=15

Substitute

x= 22

22-7? =15

SubTerm

Subtract term

15=15 ✓

An identity occurs when the left-hand side and the right-hand side of an equation are equal to one another. Since substituting x=22 resulted in an identity, our solution is correct.