The equation is
.
Case 1: If a = b Then
\
Case 2: If a =
b Then

Solve equation for case 1.
\
Apply subtraction property of equality: Subtract 7 from each side.
\
(Apply additive inverse property:
)
(Subtract:
)
Solve equation for case 2.
\
Apply subtraction property of equality: Subtract 7 from each side.
\
(Apply additive inverse property:
)
(Subtract:
)
Graph the solution on a number line.
The equality solution set is {
2 or
12}.