1/3(2x-3y)+1/2(2x-3y)-1/6(2x-3y)-5/3(2x-3y)
=2/3x-y+x-3/2y-1/3x+1/2y-10/3x+5y
=(2/3+1-1/3-10/3)x+(-1-3/2+1/2+5)y
=-2x+3y