Factorise x^2+2x-8

Firstly, note the general equation for a quadratic: ax^2+bx+c. We can see that in the above equation, a=1, b=2 and c=-8. When factorising we have to consider the product ac and b. ac=1(-8)=-8 and b=2. Now think, what two numbers multiply to give -8 and add to give 2? That would be 4 and -2. So now the equation becomes (x-2)(x+4) which is the answer.