Respuesta :
(4)(y^2+4y-21)=0
BY MIDDLE TERM SPLITTING
(4){y^2+(7y-3y)-21}=0
(4)(y^2+7y-3y-21)=0
(4){(y^2+7y)-(3y+21)}=0
(4){y(y+7)-3(y+7)}=0
(4)(y-3)(y+7)=0
HOPE THIS WILL HELP U
(4)(y^2+4y-21)=0
BY MIDDLE TERM SPLITTING
(4){y^2+(7y-3y)-21}=0
(4)(y^2+7y-3y-21)=0
(4){(y^2+7y)-(3y+21)}=0
(4){y(y+7)-3(y+7)}=0
(4)(y-3)(y+7)=0
HOPE THIS WILL HELP U