原式=(-4又3/17)×2又2/15-8又3/17×14又13/15+4×14又13/15
=(-4又3/17)×2又2/15+(-8又3/17+4)×14又13/15
=(-4又3/17)×2又2/15+(-4又3/17)×14又13/15
=(-4又3/17)×(2又2/15+14又13/15)
=-4又3/17×17
=-71/17×17
= -71