超简单的计算题3又2分之1乘负七分之五减去负七分之五乘2又二分之一减去负二分之一除以五分之七?把步骤写上..白给分的题..

原式=((3+1/2)*(-5/7)-(-5/7)*(2+1/2)-(-1/2)/(7/5)
=(3+1/2)*(-5/7)-(-5/7)*(2+1/2)-(1/2)*(-5/7)
=(-5/7)*(3+1/2-2-1/2-1/2)
=(-5/7)*(1/2)
=-5/14
原式=((3+1/2)*(-5/7)-(-5/7)*(2+1/2)-(-1/2)/(7/5)
=(7/2)*(-5/7)+(5/7)*(5/2)+(1/2)*(5/7)
=(-35/14)+25/14+5/14
=(-35+25+5)/14
=-5/14
=0.357
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
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

(3+1/2)*(-5/7)-(-5/7)*(2+1/2)-(-1/2)/(7/5)
=(3+1/2)*(-5/7)-(-5/7)*(2+1/2)-(1/2)*(-5/7)
=(-5/7)*(3+1/2-2-1/2-1/2)
=(-5/7)*(1/2)
=-5/14

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

(3+1/2)*(-5/7)-(-5/7)*(2+1/2)-(-1/2)/(7/5)
=(7/2)*(-5/7)+(5/7)*(5/2)+(1/2)*(5/7)
=(-35/14)+25/14+5/14
=(-35+25+5)/14
=-5/14
=0.357