To factorise you need to look at common factors. And it needs to be put into the expression (x+/- y)(x+/- v)For X2-X-12, you need two numbers that times to make -12 and add to make -1-1X12, -12X1, -6X2, -2X6, -4X3, -3X4Out of the options -4 and 3 add to make -1Therefore, (x-4)(x+3) is the factorisation