Factor and check x^2 - 7x - 8 = 0

x^2 - 7x - 8 = 0

(x )(x ) ( -8)( +1)=0

(x-8) (x+1) = 0

Check:

(x-8) (x+1) = 0

(x)(x) (x)(+1) (-8)(x) (-8)(+1)=0

x^2 +x -8x -8=0

x^2 - 7x - 8 = 0