3=-6+u

Solution for 3=-6+u equation:

Simplifying
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 = -9
-1u = -9

Divide each side by '-1'.
u = 9

Simplifying
u = 9