

The equations are
\
(Equation 1)
(Equation 2)
Since
,
Rewrite the first equation for x.
\
Apply division property of equality: Divide each side by 2.
\
(Cancel common terms)
(Divide:
)
Now Substitute 6 for x in either equation to find the value of y.
\
(Equation 2)
(Replace x by 6)
Apply subtraction property of equality: Subtract 6 from each side.
\
Apply commutative property of addition:
.

(Apply additive inverse property:
)
(Apply additive identity property:
)
(Subtract:
)
Apply division property of equality: Divide each side by 5.
\
(Cancel common terms)
(Divide:
)
(Multiply each side by negative one)
(Product of two same signs is positive)
The solution is 
The solution is
.