-42=3(6+8b)+6(-3b-7)

Solution for -42=3(6+8b)+6(-3b-7) equation:

Simplifying
-42 = 3(6 + 8b) + 6(-3b + -7)
-42 = (6 * 3 + 8b * 3) + 6(-3b + -7)
-42 = (18 + 24b) + 6(-3b + -7)

Reorder the terms:
-42 = 18 + 24b + 6(-7 + -3b)
-42 = 18 + 24b + (-7 * 6 + -3b * 6)
-42 = 18 + 24b + (-42 + -18b)

Reorder the terms:
-42 = 18 + -42 + 24b + -18b

Combine like terms: 18 + -42 = -24
-42 = -24 + 24b + -18b

Combine like terms: 24b + -18b = 6b
-42 = -24 + 6b

Solving
-42 = -24 + 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.
-42 + -6b = -24 + 6b + -6b

Combine like terms: 6b + -6b = 0
-42 + -6b = -24 + 0
-42 + -6b = -24

Add '42' to each side of the equation.
-42 + 42 + -6b = -24 + 42

Combine like terms: -42 + 42 = 0
0 + -6b = -24 + 42
-6b = -24 + 42

Combine like terms: -24 + 42 = 18
-6b = 18

Divide each side by '-6'.
b = -3

Simplifying
b = -3