31=3(u+2)-8u

Solution for 31=3(u+2)-8u equation:

Simplifying
31 = 3(u + 2) + -8u

Reorder the terms:
31 = 3(2 + u) + -8u
31 = (2 * 3 + u * 3) + -8u
31 = (6 + 3u) + -8u

Combine like terms: 3u + -8u = -5u
31 = 6 + -5u

Solving
31 = 6 + -5u

Solving for variable 'u'.

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

Add '5u' to each side of the equation.
31 + 5u = 6 + -5u + 5u

Combine like terms: -5u + 5u = 0
31 + 5u = 6 + 0
31 + 5u = 6

Add '-31' to each side of the equation.
31 + -31 + 5u = 6 + -31

Combine like terms: 31 + -31 = 0
0 + 5u = 6 + -31
5u = 6 + -31

Combine like terms: 6 + -31 = -25
5u = -25

Divide each side by '5'.
u = -5

Simplifying
u = -5