The equations are
\ (equation 1)
(equation 2)
Since
Rewrite the first equation for x.
\Apply subtraction property of equality: Subtract 2x from each side.
\Apply commutative property of addition: .
(Apply additive inverse property:
)
(Apply additive identity property:
)
Now Substitute for y in either equation to find the value of x.
(equation 2)
(Replace
)
(Product of two same signs is positive)
Apply commutative property of addition: .
(Add:
)
Apply addition property of equality: Add 9 to each side.
\ (Apply additive inverse property:
)
(Apply additive identity property:
)
(Add:
)
Apply division property of equality: Divide each side by 6.
\ (Cancel common terms)
(Cancel common terms)
Now
(Replace y by
)
(Product of two same signs is positive)
(Add:
)
The solution is
The solution is .