78=-2(b+3)-2(6+7b)

Solution for 78=-2(b+3)-2(6+7b) equation:

Simplifying
78 = -2(b + 3) + -2(6 + 7b)

Reorder the terms:
78 = -2(3 + b) + -2(6 + 7b)
78 = (3 * -2 + b * -2) + -2(6 + 7b)
78 = (-6 + -2b) + -2(6 + 7b)
78 = -6 + -2b + (6 * -2 + 7b * -2)
78 = -6 + -2b + (-12 + -14b)

Reorder the terms:
78 = -6 + -12 + -2b + -14b

Combine like terms: -6 + -12 = -18
78 = -18 + -2b + -14b

Combine like terms: -2b + -14b = -16b
78 = -18 + -16b

Solving
78 = -18 + -16b

Solving for variable 'b'.

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

Add '16b' to each side of the equation.
78 + 16b = -18 + -16b + 16b

Combine like terms: -16b + 16b = 0
78 + 16b = -18 + 0
78 + 16b = -18

Add '-78' to each side of the equation.
78 + -78 + 16b = -18 + -78

Combine like terms: 78 + -78 = 0
0 + 16b = -18 + -78
16b = -18 + -78

Combine like terms: -18 + -78 = -96
16b = -96

Divide each side by '16'.
b = -6

Simplifying
b = -6