could someone help me with this greatest common factor?

Question

Factor the following by taking out the greatest common factor.

16x+40y

 

i thought the answer was 4(4x+10y) i don't get what im doing wrong

Answer 1

Hi Michael,

 

It helps to figure all the possible factors each number can have.

 

So for 16, we have:

1 * 16

2 * 8

4 * 4

 

For 40, we have:

1 * 40

2 * 20

4 * 10

5 * 8

 

The common factors for 16 and 40 are: 2, 4, and 8.  Making 8 the greatest common factor.

 

So, the answer should be 8(2x + 5y).

 

I hope this helps.

Answer 2

The greatest common factor is 8, not 4.

 

16x + 40y

 

16 = 8(2)= 4(2)(2)= 2(2)(2)(2)

40 = 4(10)= 2(2)(2)(5)

The largest common factor of 16 and 40

is 2(2)(2)= 8

 

16x+40y = 8(2x) + 8(5y) = 8(2x+5y)