-800=-20(-5b)

Solution for -800=-20(-5b) equation:

Simplifying
-800 = -20(-5b)

Remove parenthesis around (-5b)
-800 = -20 * -5b

Multiply -20 * -5
-800 = 100b

Solving
-800 = 100b

Solving for variable 'b'.

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

Add '-100b' to each side of the equation.
-800 + -100b = 100b + -100b

Combine like terms: 100b + -100b = 0
-800 + -100b = 0

Add '800' to each side of the equation.
-800 + 800 + -100b = 0 + 800

Combine like terms: -800 + 800 = 0
0 + -100b = 0 + 800
-100b = 0 + 800

Combine like terms: 0 + 800 = 800
-100b = 800

Divide each side by '-100'.
b = -8

Simplifying
b = -8