72=3u+6u

Solution for 72=3u+6u equation:

Simplifying
72 = 3u + 6u

Combine like terms: 3u + 6u = 9u
72 = 9u

Solving
72 = 9u

Solving for variable 'u'.

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

Add '-9u' to each side of the equation.
72 + -9u = 9u + -9u

Combine like terms: 9u + -9u = 0
72 + -9u = 0

Add '-72' to each side of the equation.
72 + -72 + -9u = 0 + -72

Combine like terms: 72 + -72 = 0
0 + -9u = 0 + -72
-9u = 0 + -72

Combine like terms: 0 + -72 = -72
-9u = -72

Divide each side by '-9'.
u = 8

Simplifying
u = 8