-8u+3(u-2)=-21

Solution for -8u+3(u-2)=-21 equation:

Simplifying
-8u + 3(u + -2) = -21

Reorder the terms:
-8u + 3(-2 + u) = -21
-8u + (-2 * 3 + u * 3) = -21
-8u + (-6 + 3u) = -21

Reorder the terms:
-6 + -8u + 3u = -21

Combine like terms: -8u + 3u = -5u
-6 + -5u = -21

Solving
-6 + -5u = -21

Solving for variable 'u'.

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

Add '6' to each side of the equation.
-6 + 6 + -5u = -21 + 6

Combine like terms: -6 + 6 = 0
0 + -5u = -21 + 6
-5u = -21 + 6

Combine like terms: -21 + 6 = -15
-5u = -15

Divide each side by '-5'.
u = 3

Simplifying
u = 3