-123=3-7(5b+8)

Solution for -123=3-7(5b+8) equation:

Simplifying
-123 = 3 + -7(5b + 8)

Reorder the terms:
-123 = 3 + -7(8 + 5b)
-123 = 3 + (8 * -7 + 5b * -7)
-123 = 3 + (-56 + -35b)

Combine like terms: 3 + -56 = -53
-123 = -53 + -35b

Solving
-123 = -53 + -35b

Solving for variable 'b'.

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

Add '35b' to each side of the equation.
-123 + 35b = -53 + -35b + 35b

Combine like terms: -35b + 35b = 0
-123 + 35b = -53 + 0
-123 + 35b = -53

Add '123' to each side of the equation.
-123 + 123 + 35b = -53 + 123

Combine like terms: -123 + 123 = 0
0 + 35b = -53 + 123
35b = -53 + 123

Combine like terms: -53 + 123 = 70
35b = 70

Divide each side by '35'.
b = 2

Simplifying
b = 2