-42=3(u-9)

Solution for -42=3(u-9) equation:

Simplifying
-42 = 3(u + -9)

Reorder the terms:
-42 = 3(-9 + u)
-42 = (-9 * 3 + u * 3)
-42 = (-27 + 3u)

Solving
-42 = -27 + 3u

Solving for variable 'u'.

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

Add '-3u' to each side of the equation.
-42 + -3u = -27 + 3u + -3u

Combine like terms: 3u + -3u = 0
-42 + -3u = -27 + 0
-42 + -3u = -27

Add '42' to each side of the equation.
-42 + 42 + -3u = -27 + 42

Combine like terms: -42 + 42 = 0
0 + -3u = -27 + 42
-3u = -27 + 42

Combine like terms: -27 + 42 = 15
-3u = 15

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

Simplifying
u = -5