If the first term is n^2, then fisr make the equation =0, which would be n^2+7n+10. So what number multiplies to positive 10 and adds up to positive 7? 5 and 2. So factor the equation into (n+5)(n+2)=0. To make the equation 0, one of the parts have to be zero. The cases would be n=-5, -2
