what is the common factor

melody, i would like to say thank you, you are the reason i passed math 

Hi Sadpumpkin,

Hopefully this will cheer you up a bit  :)

5x-7 = +1(5x-7)

and

7-5x= -1(5x-7)

So the  common factor is   5x-7      OR   7-5x   is you prefer