Well the GCF is a number or variable you can get out of your terms and then use it to multiply it by the factored form and get the same thing as the beginning, what number can be divided by and fits in both 32 and -48, well 8 fits in 32 does it also fit in 48?? yes it does so lets set it how any times does 8 fit in 32?? well it fits 3 times, and how mny times does it fit in -48?? well it fits -6 times, this means our factored form will look like 8(4-6), now is there a number that can still fit in the numbers inside the parenthesis?? yes the numbers can still be simplified by 2. how many times does 2 fit in 4?? 2 times and how many times does 2 fit in -6, well -3 times, now multiply your first GCF by your second GCF (8*2) this gives you 15 so now your factored form should look like 16(2-3), now multiply it does it give you 32 and -48?? it does so your GCF and factor is correct