1、原式=(7/3*-5/7)-(-5/7*5/2)-((-1/2)/7/5))
=-3/5+25/14+5/14
=-3/5+30/14
=108/70
=54/35
2、原式=7/3*(-5/7-((-5/7*5/2)-((-1/2)/7/5)))
=7/3*(-5/7+25/14+5/14)
=7/3*20/14
=10/3
1、原式=(7/3*-5/7)-(-5/7*5/2)-((-1/2)/7/5))
=-3/5+25/14+5/14
=-3/5+30/14
=108/70
=54/35
2、原式=7/3*(-5/7-((-5/7*5/2)-((-1/2)/7/5)))
=7/3*(-5/7+25/14+5/14)
=7/3*20/14
=10/3