Factor and check x^2 - 18x + 80 = 0

x^2 - 18x + 80 = 0

(x )(x ) ( -10)( -8)=0

(x-10) (x-8) = 0

Check:

(x-10) (x-8) = 0

(x)(x) (x)(-8) (-10)(x) (-10)(-8)=0

x^2 -8x -10x +80=0

x^2 - 18x + 80 = 0