How do you solve x^2+4x-12=0?

1 Answer
Nov 17, 2016

(x+6)(x-2) =0 gives

x=2" or "x = -6

Explanation:

x^2 +4x -12 = 0

Factorise this quadratic trinomial first.

Find factors of 12 which subtract (because of the MINUS) to make 4.

The correct factors will be 6 and 2

Their signs must be DIFFERENT (because of the MINUS 12)

The greater must be positive (because of the PLUS 4)

(x+6)(x-2) =0

Now either of the two factors can be 0, to give the product of 0.

x+6=0 " "rarr x =-6

x-2=0" "rarr x =2