N+21=3N

Solution for N+21=3N equation:

Simplifying
N + 21 = 3N

Reorder the terms:
21 + N = 3N

Solving
21 + N = 3N

Solving for variable 'N'.

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

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

Combine like terms: N + -3N = -2N
21 + -2N = 3N + -3N

Combine like terms: 3N + -3N = 0
21 + -2N = 0

Add '-21' to each side of the equation.
21 + -21 + -2N = 0 + -21

Combine like terms: 21 + -21 = 0
0 + -2N = 0 + -21
-2N = 0 + -21

Combine like terms: 0 + -21 = -21
-2N = -21

Divide each side by '-2'.
N = 10.5

Simplifying
N = 10.5