Factor and check: z^2 -9z+20=0

Asked by AnneS2 12 years ago 9/12/2013 3:26 AM

Last updated by anonymous 12 years ago 9/13/2013 11:41 AM

Answered by CherieS 12 years ago 9/13/2013 11:41 AM

z^2 -9z+20=0

(z )(z ) ( -5)( -4)=0

(z-5) (z-4) = 0

Check:

(z-5) (z-4) = 0

(z)(z) (z)(-4) (-5)(z) (-5)(-4)=0

z^2 -4z -5z +20=0

z^2 -9z +20=0