9[n+2(n-21)]=45

Solution for 9[n+2(n-21)]=45 equation:

Simplifying
9[n + 2(n + -21)] = 45

Reorder the terms:
9[n + 2(-21 + n)] = 45
9[n + (-21 * 2 + n * 2)] = 45
9[n + (-42 + 2n)] = 45

Reorder the terms:
9[-42 + n + 2n] = 45

Combine like terms: n + 2n = 3n
9[-42 + 3n] = 45
[-42 * 9 + 3n * 9] = 45
[-378 + 27n] = 45

Solving
-378 + 27n = 45

Solving for variable 'n'.

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

Add '378' to each side of the equation.
-378 + 378 + 27n = 45 + 378

Combine like terms: -378 + 378 = 0
0 + 27n = 45 + 378
27n = 45 + 378

Combine like terms: 45 + 378 = 423
27n = 423

Divide each side by '27'.
n = 15.66666667

Simplifying
n = 15.66666667