Verified Answer :

Simplifying
u(x) = -2 + -2x + 7

Multiply u * x
ux = -2 + -2x + 7

Reorder the terms:
ux = -2 + 7 + -2x

Combine like terms: -2 + 7 = 5
ux = 5 + -2x

Solving
ux = 5 + -2x

Solving for variable 'u'.

Move all terms containing u to the left, all other terms to the right.

Divide each side by 'x'.
u = 5x-1 + -2

Simplifying
u = 5x-1 + -2

Reorder the terms:
u = -2 + 5x-1