The system of equations are
and
.
Equation (1)
Equation (2)
Solve the second equation for z.
\Apply subtraction property of equality: Subtract 7y from each side.
\
Rearrange the terms using commutative property of addition: a + b = b + a.
\
(Apply additive inverse property:
)
(Apply additive identity property:
)
Apply multiplication property of equality: Multiply each side by negative 1.
\
(Product of two same signs is positive)
Substitute
in
.

Distribute terms using distributive property: a( b
c ) = ab
ac.

(Multiply:
)
(Add:
)
Apply addition property of equality: Add 180 to each side.
\
(Apply additive inverse property:
)
(Apply additive identity property:
)
(Add:
)
Apply division property of equality: Divide each side by 29.
\
(Cancel common terms)
Now, find the z value by substituting
in
.

(Multiply:
)
(Subtract:
)
The system of solution is
.