Answer:
you need to substitute f(x)=0, there are two possible answers: x1=-6, x2=3
Step-by-step explanation:
[tex]f(x) = (x + 6)(x - 3) \\ f(x) = 0 \\ 0 = (x + 6)(x - 3) \\ swap \: it \\ (x + 6)(x - 3) = 0 \\ x + 6 = 0 \\ x - 3 = 0 \\ x = - 6 \\ x = 3 \\ x1 = - 6 \\ x2 = 3[/tex]
