Factoring what 2 numbers multiply to get -12 and add to get -4? -6 and 2 (x-6)(x+2)=0 set to zero x-6=0 x=6 x+2=0 x=-2
x=-2 and 6
complete the square isolate x terms (x^2-4x)-12=0 take 1/2 of -4 and square it ((-2)^2=4) now add positive and neagtive inside (x^2-4x+4-4)-12=0 factor perfect square ((x-2)^2-4)-12=0 get rid of parenthasees (x-2)^2-4-12=0 (x-2)^2-16=0 add 16 both sides (x-2)^2=16 sqrt both sides, don't forget positive an dneagit ve roots x-2=+/-4 add 2 to both sides x=2+/-4 x=2+4=6 x=2-4=-2