Solve x^2 – 6x – 8 = 0 Write your answer in the form a ± √ b where a and b are integers. (Higher tier paper)

To solve this equation we cant use the PSF method, as nothing multiplies to -8 and adds to -6. (Also in the question it says the answer will be in a±b which is normally what you get when you can't factorise). So we should use either completing the square, or the quadratic formula. As there's only one x^2, and the x value is even, completing the square will be perfect. (x-3)^2-9-8=0   We create the bracket, with the second value being half the number before the x (the x-coefficient) then subtracting its square, 9, and putting the -8 on the end. (x-3)^2=17   We combine the -9 and the -8, and add 17 to both sides of the equation. x-3=±√17   We square root both sides, remembering the plus minus symbol. x=3±√17   We add 3 to both sides, giving us the final answer.