Let's perform the [synthetic division]
#color(white)(aaaa)##2##color(white)(aaaaaa)##|##color(white)(aa)##1##color(white)(aaaa)##-8##color(white)(aaaaaa)##10##color(white)(aaaaaaa)##2##color(white)(aaaaaaa)##4#
#color(white)(aaaaaaaaaaaa)#_________
#color(white)(aaaa)##color(white)(aaaaaaa)##|##color(white)(aaaa)##color(white)(aaaaa)##2##color(white)(aaaa)##-12##color(white)(aaaaa)##-4##color(white)(aaaaaa)##-4#
#color(white)(aaaaaaaaaaaa)#________
#color(white)(aaaa)##color(white)(aaaaaaa)##|##color(white)(aaa)##1##color(white)(aaa)##-6##color(white)(aaaaa)##-2##color(white)(aaaaaa)##-2##color(white)(aaaaaaa)##color(red)(0)#
The remainder is #color(red)(0)# and the quotient is #=y^3-6y^2-2y-2#
#(y^4-8y^3+10y^2+2y+4)/(y-2)=y^3-6y^2-2y-2#