3(b-4)-5(-3-4b)=72

Solution for 3(b-4)-5(-3-4b)=72 equation:

Simplifying
3(b + -4) + -5(-3 + -4b) = 72

Reorder the terms:
3(-4 + b) + -5(-3 + -4b) = 72
(-4 * 3 + b * 3) + -5(-3 + -4b) = 72
(-12 + 3b) + -5(-3 + -4b) = 72
-12 + 3b + (-3 * -5 + -4b * -5) = 72
-12 + 3b + (15 + 20b) = 72

Reorder the terms:
-12 + 15 + 3b + 20b = 72

Combine like terms: -12 + 15 = 3
3 + 3b + 20b = 72

Combine like terms: 3b + 20b = 23b
3 + 23b = 72

Solving
3 + 23b = 72

Solving for variable 'b'.

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

Add '-3' to each side of the equation.
3 + -3 + 23b = 72 + -3

Combine like terms: 3 + -3 = 0
0 + 23b = 72 + -3
23b = 72 + -3

Combine like terms: 72 + -3 = 69
23b = 69

Divide each side by '23'.
b = 3

Simplifying
b = 3