108=.5(12)(b+13)

Solution for 108=.5(12)(b+13) equation:

Simplifying
108 = 0.5(12)(b + 13)

Reorder the terms:
108 = 0.5 * 12(13 + b)

Multiply 0.5 * 12
108 = 6(13 + b)
108 = (13 * 6 + b * 6)
108 = (78 + 6b)

Solving
108 = 78 + 6b

Solving for variable 'b'.

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

Add '-6b' to each side of the equation.
108 + -6b = 78 + 6b + -6b

Combine like terms: 6b + -6b = 0
108 + -6b = 78 + 0
108 + -6b = 78

Add '-108' to each side of the equation.
108 + -108 + -6b = 78 + -108

Combine like terms: 108 + -108 = 0
0 + -6b = 78 + -108
-6b = 78 + -108

Combine like terms: 78 + -108 = -30
-6b = -30

Divide each side by '-6'.
b = 5

Simplifying
b = 5