What are the zeros of the polynomial function f(x)=x^2+5x+6

Find 2 numbers that multiply to 6 and add to 5.

3*2 = 6
3+2 = 5

x^2 + 5x+6 = (x+3)(x+2) = 0

Set each factor equal to zero.
x+3 = 0   >  x = -3
x+2 = 0 >  x = -2

There are two zeros at -2 and -3.