Given: #(-x^3 - 6x^2 + 3x += 4)/(2x^2 - x)#
Using long division:
#2x^2 - x|bar(-x^3 -6x^2+3x+4)#
What times #2x^2 = -x^3#? #" "-1/2x#
#" "-1/2x#
#2x^2 - x|bar(-x^3 -6x^2+3x+4)#
#" "ul (-x^3 + 1/2x^2)#
#" "-13/2 x^2 + 3x#
What times #2x^2 = -13/2x^2#? #" "-13/4#
#" "-1/2x -13/4#
#2x^2 - x|bar(-x^3 -6x^2+3x+4" ")#
#" "ul (-x^3 + 1/2x^2)#
#" "-13/2 x^2 + 3x#
#" "ul(-13/2x^2 + 13/4x#
#" "-1/4x + 4# This is the remainder
#(-x^3 - 6x^2 + 3x += 4)/(2x^2 - x) = -1/2x - 13/4 + (-x/4 + 4)/(2x^2 - x)#
The remainder can be simplified if desired.