Respuesta :

olemakpadu
 20 and 45x

We look for a number that can go into both numbers.

5 into 20 is 4 and 5 into 45x is 9x.

5:      20       45x

         4           9x

So no other number can go into 4 and 9x again.

So the GCF of 20 and 45x is 5.     

Hope this explains it.
The greatest common factor is 5