What is the greatest common factor of 8x and 40y?

5

5xy

320

320xy

none of the above.

Step-by-step explanation:

when we talk about greatest common factor of 8 x and 40 y

8 x = 2 * 2 * 2 * x ... (1)

40 y = 2 * 2 * 2 * 5 * y ... (2)

when we see both equation (1) and (2)

then we can clearly see

that the greatest common are 2 * 2 * 2

so, the greatest common will be 2 * 2 * 2 = 8

hence, the correct answer will be none of the above.

8.

Step-by-step explanation:

It's none of those. It is 8, because 8 is a factor of 40 (and of 8 of course).