21=(w-3)2+w

Solution for 21=(w-3)2+w equation:

Simplifying
21 = (w + -3) * 2 + w

Reorder the terms:
21 = (-3 + w) * 2 + w

Reorder the terms for easier multiplication:
21 = 2(-3 + w) + w
21 = (-3 * 2 + w * 2) + w
21 = (-6 + 2w) + w

Combine like terms: 2w + w = 3w
21 = -6 + 3w

Solving
21 = -6 + 3w

Solving for variable 'w'.

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

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

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

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

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

Combine like terms: -6 + -21 = -27
-3w = -27

Divide each side by '-3'.
w = 9

Simplifying
w = 9