Answer:
x = 3
Explanation:
4(5x−20)=−20 | Given
20x - 80 = -20 | Distribute the number on the outside (multiply all numbers on the inside by the number on the outside, 4×5x and 4×-20)
20x = 60 | Add 80 to both sides (do the opposite operation, if its a negative number add it to both sides)
x = 3 | Divide both sides by 20x (20x turns into x and 60 turns into 3 via 60÷20)