Ineed to factor 5a^2 + 7a + 6b^2 - 4b but i can't figure it it possibly be prime?

I kind of forgot how to do it but here is what I know so far : first you separate the two parts into (5a^2 + 7a) + (6b^2-4b). This process is called grouping. Now you find the greatest common factor in both of them which later your equation will be a(5a + 7) +2b(3b - 2). That is all I can remember so hope that helped