6x+8y=7004x+7y=500

【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= 6x+8y=7004x+7y=500 {6(x-y)-7(x+y)=21 {2(x-y)-5(x+y)=-1 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 已知x+y=6,xy=7,试求x*x+y*y,x*x-y*y的值 已知X*X+Y*Y+6X-8Y+25=0 求（Y/X)+(X/Y)-2=? x*x+2x-y*y+6y-8=0,x+y不等于2,求x-y的值 已知|5x-y-8|+(7y-x+2)=0则4x+6y 求几个方程组的答案 ｛2x+y=2 {3x-y=7 x=?y=?{x+2y=50 {3x=2y+6 x=?y=?{x+y=40 {10x+8y=370 x、y=?{x+y=5.8 {y=3x+0.6 x=?y=? 已知：2x+y=6,x-3y=1 求7y(x-3y)(x-3y)-2(3y-x)(3y-x) x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 3x+2=y 5x+4=y 7x+6=y 9x+8=y 11x=y 联立方程 有的话 3x+2=y 5x+4=y 7x+6=y 9x+8=y 11x=y 3x+2=y 5X+4=Y 7X+6=Y 9X+8=y 11x=y要如何计算 3x+2=y 5x+4=y 7x+6=y 9x+8=y 11x=y怎么解 y-3x=2,y-5x=4,y-7x=6,y-9x=8,y-11x=0方程组,无 3(x+y)的平方-7(x+y)+8(x+y)的平方+6(x+y)-11(x+y)的平方=? 5x^3y-6x-7x^3y-8x=