Thực hiện phép tính:4/(y-x)(z-x)+3/(y-x)(y-z)+3/(y-z)(x-z)

4y−xz−x+3y−xy−z+3y−zx−z=4y−z+3z−x−3y−xy−xz−xy−z=y−zy−xz−xy−z=1y−xz−x