——2X-6Y=7 Y=?

——2X-6Y=7 Y=? 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 [(2x—y)(2x+y)—y(y—6x)]除以2x=多少 3(x+y)—4(x-y)=4,(x+y/2)+(x-y/6)=1.解方程组 x²-2x+y²+6y+10=0,求—9(x+y)²+(3x-2y)(2y+3x)的值 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= 已知x²+4y+y²—6y+13=0,求2x+3y的值 5x—2y=—8 7x—6y=—40 若x、y满足2x+y=6,x-3y=1,求7y(x-3y)²-2(3y-x)³的值 x+y=3 x+2y=9 3/x+1=y y-x=3 y=2x-3 y-3x=1 2(x+1)-y=6 7x-5y=-9 计算：(x—y)^7÷(y—x)^6+(—x—y)^3÷(x+y)^2 4x-(2x+y+16)/2=-6y 2x+3y=7-x-2y