The greatest common factor is the biggest number that divides all of them evenly. For this, we have
. Let's try
. Does it divide all three evenly?
![x^4/x^4 = 1\\x^7/x^4 = x^3\\x^8/x^4 = x^4](https://img.qammunity.org/2023/formulas/mathematics/high-school/ensfhpk7luf048gsvualm0hljx9py40gct.png)
Yes, because those are all whole numbers. Is there a bigger number than
which divides all three? No, there can't be, because then it wouldn't go into
evenly. (It would be too big.)
So
must be the greatest common factor.