b+(b+1)+(b+2)+(b+3)=-15

Solution for b+(b+1)+(b+2)+(b+3)=-15 equation:

Simplifying
b + (b + 1) + (b + 2) + (b + 3) = -15

Reorder the terms:
b + (1 + b) + (b + 2) + (b + 3) = -15

Remove parenthesis around (1 + b)
b + 1 + b + (b + 2) + (b + 3) = -15

Reorder the terms:
b + 1 + b + (2 + b) + (b + 3) = -15

Remove parenthesis around (2 + b)
b + 1 + b + 2 + b + (b + 3) = -15

Reorder the terms:
b + 1 + b + 2 + b + (3 + b) = -15

Remove parenthesis around (3 + b)
b + 1 + b + 2 + b + 3 + b = -15

Reorder the terms:
1 + 2 + 3 + b + b + b + b = -15

Combine like terms: 1 + 2 = 3
3 + 3 + b + b + b + b = -15

Combine like terms: 3 + 3 = 6
6 + b + b + b + b = -15

Combine like terms: b + b = 2b
6 + 2b + b + b = -15

Combine like terms: 2b + b = 3b
6 + 3b + b = -15

Combine like terms: 3b + b = 4b
6 + 4b = -15

Solving
6 + 4b = -15

Solving for variable 'b'.

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

Add '-6' to each side of the equation.
6 + -6 + 4b = -15 + -6

Combine like terms: 6 + -6 = 0
0 + 4b = -15 + -6
4b = -15 + -6

Combine like terms: -15 + -6 = -21
4b = -21

Divide each side by '4'.
b = -5.25

Simplifying
b = -5.25