3=u+6

Solution for 3=u+6 equation:

Simplifying
3 = u + 6

Reorder the terms:
3 = 6 + u

Solving
3 = 6 + u

Solving for variable 'u'.

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

Add '-1u' to each side of the equation.
3 + -1u = 6 + u + -1u

Combine like terms: u + -1u = 0
3 + -1u = 6 + 0
3 + -1u = 6

Add '-3' to each side of the equation.
3 + -3 + -1u = 6 + -3

Combine like terms: 3 + -3 = 0
0 + -1u = 6 + -3
-1u = 6 + -3

Combine like terms: 6 + -3 = 3
-1u = 3

Divide each side by '-1'.
u = -3

Simplifying
u = -3