Well the GCF is the number that can be used to simplify, or that fits in all of your numbers for example this are all small numbers so 2 should fit in all of them 2 fits in 4 two times 2 fits in 2 one time and 2 fits in 6 three times now lets check our variable, to find the GCF of the variable first chekc if they all have the same if they don't u can't get none of taht variebles out, but if they repeat in all like the a u will take out the smallest amount out, for example the a as one in the degree of 1 the other in to the 2 degree and the last one to teh 3 degree well the smallest degree will be 1 so u will only take 1 a out so now ur GCF looks like 2a... Lets check the other variables, b is used in all of them and the smallest degree is b2 so we will take out 2 b's out so now my GCF looks like 2ab2 now lets check our last variable the, the c has the smallest degree of 1 so we will only take 1 c out this means our final GCF is "2ab2c"