We perform a synthetic division
#color(white)(aaaa)##-1##color(white)(aaaa)##|##color(white)(aaaa)##10##color(white)(aaaa)##5##color(white)(aaaaa)##4##color(white)(aaaaaa)##0##color(white)(aaaa)##-9#
#color(white)(aaaaaa)##color(white)(aaaaa)##|##color(white)(aaa)##color(white)(aaaa)##-10##color(white)(aaaaa)##5##color(white)(aaaaa)##-9##color(white)(aaaaa)##9#
#color(white)(aaaaaaaaaa)#------------------------------------------------------------
#color(white)(aaaa)##color(white)(aaaaaa)##color(white)(aaaaaa)##10##color(white)(aaa)##-5##color(white)(aaaaa)##9##color(white)(aaaaa)##-9##color(white)(aaaaa)##color(red)(0)#
The remainder is #=0#
The quotient is #=10x^3-5x^2+9x-9#