Factor completely x2 - 7x + 18

Prime

(x - 9) (x - 2)

(x - 9) (x + 2)

(x + 9) (x + 2)

x2 - 7x + 18

is prime

there is no way you can make two numbers multiply to get positive 18 and add to get negative 7

(x - 9) (x - 2) = x^2 - 11x + 18

(x - 9) (x + 2) = x^2 - 7x - 18

(x + 9) (x + 2) = x^2 + 11x + 18