3(b-21)+3(b-4)=27

Solution for 3(b-21)+3(b-4)=27 equation:

Simplifying
3(b + -21) + 3(b + -4) = 27

Reorder the terms:
3(-21 + b) + 3(b + -4) = 27
(-21 * 3 + b * 3) + 3(b + -4) = 27
(-63 + 3b) + 3(b + -4) = 27

Reorder the terms:
-63 + 3b + 3(-4 + b) = 27
-63 + 3b + (-4 * 3 + b * 3) = 27
-63 + 3b + (-12 + 3b) = 27

Reorder the terms:
-63 + -12 + 3b + 3b = 27

Combine like terms: -63 + -12 = -75
-75 + 3b + 3b = 27

Combine like terms: 3b + 3b = 6b
-75 + 6b = 27

Solving
-75 + 6b = 27

Solving for variable 'b'.

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

Add '75' to each side of the equation.
-75 + 75 + 6b = 27 + 75

Combine like terms: -75 + 75 = 0
0 + 6b = 27 + 75
6b = 27 + 75

Combine like terms: 27 + 75 = 102
6b = 102

Divide each side by '6'.
b = 17

Simplifying
b = 17