4[2x+y]-5[2x-y]=3

问题描述:

4[2x+y]-5[2x-y]=3
2[2x+y]+10[2x-y]=39

8x+4y-10x+5y=3-> 9y-2x=3得:x=1.875
4x+2y+20x-10y=39->24x-8y=39 y=0.75