Let's perform the long division
#color(white)(aaaa)##6x^4-44x^3+48x^2##color(white)(aaaa)##-2##color(white)(aaaa)##|##6x-8#
#color(white)(aaaa)##6x^4-8x^3##color(white)(aaaaaaaaaaaaaa)####color(white)(aaaa)##|##x^3-6x^2#
#color(white)(aaaaaa)##0-36x^3+48x^2##color(white)(aaaaaaaaaaaaaa)####color(white)(aaaa)#
#color(white)(aaaaaaaa)##-36x^3+48x^2##color(white)(aaaaaaaaaaaaaa)####color(white)(aaaa)#
#color(white)(aaaaaaaaaaa)##-0+0##color(white)(aaaaaaa)##-2##color(white)(aaaa)#
The quotient is #=x^3-6x^2#
The remainder is #=-2#
Therefore,
#(6x^4-44x^3+48x^2-2)/(6x-8)=x^3-6x^2-2/(6x-8)#
#=x^3-6x^2-1/(3x-4)#