9[n+2(n-20)]=45

Solution for 9[n+2(n-20)]=45 equation:

Simplifying
9[n + 2(n + -20)] = 45

Reorder the terms:
9[n + 2(-20 + n)] = 45
9[n + (-20 * 2 + n * 2)] = 45
9[n + (-40 + 2n)] = 45

Reorder the terms:
9[-40 + n + 2n] = 45

Combine like terms: n + 2n = 3n
9[-40 + 3n] = 45
[-40 * 9 + 3n * 9] = 45
[-360 + 27n] = 45

Solving
-360 + 27n = 45

Solving for variable 'n'.

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

Add '360' to each side of the equation.
-360 + 360 + 27n = 45 + 360

Combine like terms: -360 + 360 = 0
0 + 27n = 45 + 360
27n = 45 + 360

Combine like terms: 45 + 360 = 405
27n = 405

Divide each side by '27'.
n = 15

Simplifying
n = 15