Answer:
x = -18
Explanation:

Combine x and
to get
.

Subtract 21 from both sides.

Subtract 21 from 9 to get −12.

Multiply both sides by
, the reciprocal of
.
×

Express −12 ×
as a single fraction.

Multiply −12 and 3 to get −36.

Divide −36 by 2 to get −18.
x = -18
hope it helps and have a great day! =D
~sunshine~