#" "4x^3+7x^2-9x+15#
#color(magenta)(+4x^2)(x+1)-> ul(4x^3+4x^2" "larr" Subtract")#
#" "0 color(white)(x^3) +3x^2-9x+15#
#color(magenta)(+3x)(x+1)->" " ul(3x^2+3x" "larr" Subtract")#
#" "0color(white)(x^2)-12x+15#
#color(magenta)(-12)(x+1)->" "ul(-12x-12" "larr" Subtract")#
#" "0color(white)(x)color(magenta)(+27 larr" Remainder")#
#color(magenta)( 4x^2+3x-12+27/(x+1) )#