设1/(x+y)=m,1/(x-y)=n则4m+6n=3(1)9n-m=1(2)(2)*4得;36n-4m=4(3)(1)+(3)得:42n=7.n=1/6将n=1/6带入(2)得;3/2-m=1,m=1/2所以1/(x+y)=1/2,1/(x-y)=1/6所以x+y=2(4)x-y=6(5)(4)+(5)得:2x=8,x=4带入(4)得y=-2所以方程组的解为x=4,y=-2
3/4×(x-4/9)=1
解
3x/4-1/3=1
3x/4=1+1/3
3x/4=4/3
9x=16
解得x=16/9