The equations are .
Equation (1)
Equation (2)
Since the coefficient of x is same in both equations, either equation can be used for solution. Solve the second equation for x.
\According to addition property of equality: Add y to each side.
\ (Apply additive inverse property:
)
(Apply additive identity property:
)
Substitute in equation (1).
(Add:
)
According to subtraction property of equality: Subtract 8 from each side.
\ (Apply commutive property of addition:
)
(Apply additive inverse property:
)
(Apply additive identity property:
)
(Subtract:
)
(Divide each side by 4)
(Cancel common terms)
(Divide:
)
Substitute in equation
.
(Product of two different signs is negative)
(Subtract:
)
The solution is .