Well, since it says it's congruent, it's congruent. EF overbar congruent to GH overbar.
2x^2-8x-24=0
Divide the whole equation by 2.
x^2-4x-12=0
Complete the square
x^2-4x+4-16=0
(x-2)^2 -16=0
(x-2)^2=16
Take the square root of each side.
(x-2)=4 and (-(x-2))=4
x=6 and x=-2
The third one, because statistical questions have variables that can change