Factor 4n^2+9n+5
4n^2 + 9n + 5 = 0
ab = 20, a+b = 9
5 and 4 work because 5x4=20, 5+4=9
4n^2 + 4n + 5n + 5 = 0
common factor
4n(n+1) + 5(n+1)=0
(4n+5)(n+1)=0
4n+5 = 0, n+1 = 0
n = -5/4, n=-1
