2（x-2)=2-7(x-2) y-2分之y-1=2-5分之y+2解题过程

x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 若x+3y=3x+2y=7,则x,y的值分别是 用因式分解法简化计算 已知：x+y=1,xy=-1/2 求:x(x+y)(x-y)-x(x+y)^2的值 答完追10分.公式法证明题x>=o,y>=0.证明.(x+y)^2/2+(x+y)/4>=(x*y^0.5)+(y*x^0.5) 已知x^2+xy=16 y^2+xy=9 求(x+y) (x-y)分别是 x+y x-y 不是乘 (x+y)/2+(x-y)/3=6 4(x+y)-3(x-y)=－2 0 求x,y分可以加. 因式分解x(x+y)(x-y)-x(x+y)^2 x+2y=2x+y+1=7x-y 求：2x-y? 解方程组(x+y)(x-2y)=-5 (x-y)(x+2y)=7 x^2+y^2=15,x+y=7,x＞y,求x-y {6(x-y)-7(x+y)=21 {2(x-y)-5(x+y)=-1 当x+y=2时7(x+y)一(x+y)+(x+y)=? 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 化简y(x+y)+(x+y)(x-y)-x^2 当x=2 y=2分1时 求代数式(x+y)(x-y)+(x-y)的平方-(x的平方-3xy)的值 解三元一次方程x-y-z=-1 3x+5y+7x=11 4x-y+2z=-1我没什么分了. 分简 xy-2y /x^2-4x+4 matlab画几个二元函数x*y/(x^2+y^2)^0.51/(x+y)x*y/(x+y)1/(x*y)sin(x+y)sin(x*y)sin(x)+sin(y)这么多,回答了再加分怎么设置上下限?