解二元一次方程组,急用!0.8x-1.7y=-75x-3y=24x+y=45x-1=1.8-x-6yx/5-y/2=-4x/15-_数学解答

解二元一次方程组,急用!
0.8x-1.7y=-7
5x-3y=2
4x+y=45
x-1=1.8-x-6y
x/5-y/2=-4
x/15-y/7=-3
(2x-y)/5=(x=y)/3=3
x/2-(2/3)y=-(2/15)
x/2-(5/3)y=-(4/3)

人气：499 ℃　时间：2020-04-15 12:07:24

解答

0.8x-1.7y=-7(1)5x-3y=2(2)(1)*50-(2)*840x-85y-40x+24y=-350-16-61y=-366y=6x=44x+y=4.5 (1)x-1=1.8-x-6y 2x+6y=2.8x+3y=1.4 (2)(1)×3-(2)12x+3y-x-3y=13.5-1.411x=12.1x=1.1y=4.5-4x=0.1 下面有点烦只怪你分太少...