Question

Find the GCF of 15y^3 and -20y. Please explain how to do this type of problem.

Thanks!

Answer 1

5y

Explanation:

First find all the factors of 15y^3 and then all the factors of -20y

15y^3 = 3 , 5 , y, y, y

-20y = 2 , 4, 5, 10, y

The GCF is 5 and y. We choose 5 because it is the greatest number and common in both sets. We also choose one y because it is common in both sets and one y is the greatest common y.

Answer = 5y

You can also do this by using the prime factorization method.

Answer 2

GCF will be 5y

Explanation:

First of all the negative signs will be excluded when finding the GCF. The GCF is calculated by multiplying together the highest power of each of the common factors.

15^3 can be split into,

3*5*y*y*y.

-20y into,

2*4*5*10*y.

We will choose 5 as it is the greatest common number in both sets and choose y as it is also common in both sets.

So, the GCF will be 5y.