To factorize the quadratic expression x^2 - 11x + 18, you need to find two numbers that multiply to the constant term (18) and add up to the coefficient of the linear term (-11). These numbers are -2 and -9 because (-2) * (-9) = 18, and (-2) + (-9) = -11.
Now, you can use these numbers to factorize the expression:
x^2 - 11x + 18 = (x - 2)(x - 9)
So, the factored form is:
(x - 2)(x - 9)