Question

Solve the quadratic by factoring.
x^2-5x-31=5

Answer 1

`x = - 4\: or \: x = 9`

Explanation:

make one side equal to zero:

`{x}^(2) - 5x - 36 = 0`

find two factors that multiply to -36 and add to -5 (-9 & 4)

`{x }^(2) - 9x + 4x - 36 = 0`

factorise

`x(x - 9) + 4(x - 9) = 0`

`(x + 4)(x - 9) = 0`

solve for x

`x = - 4 \: or \: x = 9`