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 .