3(u+2)=6u+21

Solution for 3(u+2)=6u+21 equation:

Simplifying
3(u + 2) = 6u + 21

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

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

Solving
6 + 3u = 21 + 6u

Solving for variable 'u'.

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

Add '-6u' to each side of the equation.
6 + 3u + -6u = 21 + 6u + -6u

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

Combine like terms: 6u + -6u = 0
6 + -3u = 21 + 0
6 + -3u = 21

Add '-6' to each side of the equation.
6 + -6 + -3u = 21 + -6

Combine like terms: 6 + -6 = 0
0 + -3u = 21 + -6
-3u = 21 + -6

Combine like terms: 21 + -6 = 15
-3u = 15

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

Simplifying
u = -5