方程组 0.8x-1.7y=-7 ,5x-3y=2

题目

方程组 0.8x-1.7y=-7 ,5x-3y=2
偶需要完整滴过程.030

答案

5x-3y=2
5x=3y+2
x=0.6y+0.4
0.8(0.6y+0.4)-1.7y=-7
0.48y+0.32-1.7y=-7
1.7y-0.48y=7+0.32
1.22y=7.32
y=6
x=0.6x6+0.4=3.6+0.4=4