Final answer:
The factored expression is 20x(x - 6).
Step-by-step explanation:
To factor the expression 20x^2 - 120x completely, we begin by finding the greatest common factor of the two terms. In this case, the greatest common factor is 20x. We can factor this out from both terms:
20x^2 - 120x = 20x(x - 6)
So the expression is completely factored as 20x(x - 6).