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