Suggested Answer
x^2 - 11x + 18 =0 <=> x^2 - 2x - 9x +18 = 0 <=> x(x-2) - 9(x-2) = 0 <=> (x-2)(x-9) = 0 => x -2 = 0 or x -9=0 => x=2 or x = 9.
x^2 - 11x + 18 =0 <=> x^2 - 2x - 9x +18 = 0 <=> x(x-2) - 9(x-2) = 0 <=> (x-2)(x-9) = 0 => x -2 = 0 or x -9=0 => x=2 or x = 9.