0.4x+0.3y=0.7 11x-10y=1

{二分之一x-三分之一y=1 -五分之一x-y=三分之二 ｛0.4x+0.3y=0.7 11x-10y=1 先化简再求值(x-y)(x+y)-(x-2y) 的完全平方+x(3x-5y)-(x-y)(x-2y),其中x=1/2 y y=ln(1+x),求y^10(x)? 0.5x+0.7y=35,x+0.4y=40.求x=?,y=? 用加减法解方程组:{(x+y)/6+(x-y)/10=3 (x+y)/6+(y-x)/10=-1 解方程组x+y/6+x-y/10=3,x+y/6+y-x/10=-1 y=[x-1], 3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27 { x-y/7-x+y/10=1/2 {2(x-y)+5(x+y)=3 解方程组:(x+3)(y-2)=(x-3)(y+10),(x+1)(y+3)=(x-2)(y+12) 10/x+y+3/x-y=-5 15/x+y-2/x-y=-1（用换元法解此方程组） 已知/x/+x+y=10,/y/+x-y=12.求x+y的值