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

x^2 + 8x + 7 = 0

(x )(x ) ( +1)( +7)=0

(x+1) (x+7) = 0

Check:

(x+1) (x+7) = 0

(x)(x) (x)(+7) (1)(x) (1)(7)=0

x^2 +7x +1x +7=0

x^2 +8x +7=0