Factorise x^2-x-12
To factorise this equation we want to get 2 brackets. We are looking for 2 numbers which multiply to make -12 and add to make -1. So, let's see some factors of -12: -12 = (-1) x 12; (-2) x 6; (-3) x 4; (-4) x 3; here we can see that -4 & 3 add to make -1 and since they are also factors of -12, this pair fills the criteria. So, the factorisation of x2-x-12 = (x-4)(x+3).To check if you factorised the equation correctly, we can expand the brackets to get: x2-4x+3x-12 which = x2-x-12 so we know our values of -4 and 3 are definitely correct.
