His answer works ... it gives 150, which is the same as (60 + 90) ... but he didn't deliver exactly what the problem asked for.
It asked for the GCF to be outside the parentheses, and he put '3' there.
'3' is certainly one common factor of 60 and 90, but it's far from being the
greatest one.
The GCF of 60 and 90 is actually 30 . So the absolutely positively technically correct response to the instructions in the problem would be 30(2 + 3).
