Exercise 1 Page 26

To solve an equation, we should first gather all of the variable terms on one side and all of the constant terms on the other, using the Properties of Equality.

x+9=7

SubEqn

LHS-9=RHS-9

x+9-9=7-9

SubTerms

Subtract terms

x=-2

We will check our solution by substituting this result back into the original equation and simplifying. If doing so results in an identity, our solution is correct. An identity is when both sides of the equation are exactly the same.

x+9=7

Substitute

x= -2

-2+9? =7

AddTerms

Add terms

7=7

Since substituting x=-2 resulted in an identity, our solution is correct.