n+21=2n

Solution for n+21=2n equation:

Simplifying
n + 21 = 2n

Reorder the terms:
21 + n = 2n

Solving
21 + n = 2n

Solving for variable 'n'.

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

Add '-2n' to each side of the equation.
21 + n + -2n = 2n + -2n

Combine like terms: n + -2n = -1n
21 + -1n = 2n + -2n

Combine like terms: 2n + -2n = 0
21 + -1n = 0

Add '-21' to each side of the equation.
21 + -21 + -1n = 0 + -21

Combine like terms: 21 + -21 = 0
0 + -1n = 0 + -21
-1n = 0 + -21

Combine like terms: 0 + -21 = -21
-1n = -21

Divide each side by '-1'.
n = 21

Simplifying
n = 21