

The equation is
.
Combine like terms using distributive property: ab
ac = a( b
c).

Apply subtraction property of equality: Subtract 4x from each side.
\
Rearrange the terms using commutative property of addition:
.
(Multiply:
)
(Subtract:
)
Apply division property of equality: Divide each side by (7+5x).
\
(Cancel common terms)

(Substitute
)
(Multiply:
)
(Add:
)
(Divide:
)
The solution is
.