Question

x+y乘3分之1-x-y乘6分之1的积=7和x+y乘4分之1+x-y乘6分之1的积=1这两个是二元一次方程,求x,y.

Answer 1

1/3(x+y)-1/6(x-y)=7

1/4(x+y)+1/6(x-y)=1

两式相加得

7/12(x+y)=8

即(x+y)=96/7

带入上式得

x-y=-102/7

x+y=96/7

x=-3/7

y=99/7