s+(s+4)+3(s+4)=91

Solution for s+(s+4)+3(s+4)=91 equation:

Simplifying
s + (s + 4) + 3(s + 4) = 91

Reorder the terms:
s + (4 + s) + 3(s + 4) = 91

Remove parenthesis around (4 + s)
s + 4 + s + 3(s + 4) = 91

Reorder the terms:
s + 4 + s + 3(4 + s) = 91
s + 4 + s + (4 * 3 + s * 3) = 91
s + 4 + s + (12 + 3s) = 91

Reorder the terms:
4 + 12 + s + s + 3s = 91

Combine like terms: 4 + 12 = 16
16 + s + s + 3s = 91

Combine like terms: s + s = 2s
16 + 2s + 3s = 91

Combine like terms: 2s + 3s = 5s
16 + 5s = 91

Solving
16 + 5s = 91

Solving for variable 's'.

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

Add '-16' to each side of the equation.
16 + -16 + 5s = 91 + -16

Combine like terms: 16 + -16 = 0
0 + 5s = 91 + -16
5s = 91 + -16

Combine like terms: 91 + -16 = 75
5s = 75

Divide each side by '5'.
s = 15

Simplifying
s = 15