Answer:
5x²y
Step-by-step explanation:
First, factor the two monomials into their prime factors:
15x²y³ = 3 × 5 × x × x × y × y × y
-20x³yz = -1 ×2 × 2 × 5 × x × x × x × y × z
Now pick the common factors (shown in bold below):
15x²y³ = 3 × 5 × x × x × y × y × y
-20x³yz = -1 ×2 × 2 × 5 × x × x × x × y × z
Now multiply together the common factors:
The common factors are: 5, x, x, y
The GCF is 5x²y
