y=x^2

x-y/x-x+y/y-(x+y)(x-y)/y²y/x=2以上错误,修改如下：y/x=2→y=2x(x-y)/x-(x+y)/y-(x+y)(x-y)/y^2=((xy-y^2)-(x^2+xy))/xy-(x^2-y^2)/y

若x-y=2(x+y),求代数式x-y/x+y+x+y/x-y求代数式x+y分之x-y+x-y分之x+y已知:y=ax的3次方+bx+3,当x=-1/2时,y=-7,试求x=1/2时,y的值(x-y)/(x+y)+(x+y)/(x-y)x-

填空：x-y/x+y=()/x^2-y^2分子分母同时乘以x-y即(x-y)^2/(x+y)(x-y)=(x-y)^2/x^2-y^2空格中填（x-y）^2(x-y)/(x+y)=[(x-y)(x-y)]/[(x+y)(x-y)]=(x-y

（x-y)2•(y-x)³(x-y)=?答：（x-y)2•(y-x)³(x-y)==(x-y)²×(y-x)³(x-y)=(x-y)³×(y-x)³=-(x

y"+y'-2y=2xy"+y'-2y=2x先求y"+y'-2y=0的通r²+r-2=0,r=1或-2y=ce^x+de^(-2x)再求一个特解,设特解为y=ax+b,则y'=a,y"=0代入原式得0+a-2ax-2b=2x可求得

微分方程y"-2y'+y=x先求对应齐次方程的特征方程为r″-2r+1=0r1=r2=1齐次方程的通解为Y=e^x(C1+C2x)再求非其次方程的特特解形式为y0=e^(λx)·x^k·(Ax+B)∵P(x)=x=e^(λx)·x∴λ=0不

(x-y)(x-2y)+(x+2y)(x-3y)-2(x-3y)(x-4y)=(x-y)(x-2y)+(x+2y)(x-3y)-2(x-3y)(x-4y)=(x-y)(x-2y)+（x-3y)[(x+2y)-2(x-4y)]=(x-y)(x

(x+y)(x-y)+(x-y)平方-(x-y)(3x-y)其中x=-2y=3分之一(x+y)(x-y)+(x-y)平方-(x-y)(3x-y)=(x-y)(x+y+x-y-3x+y)=(x-y)(-x+y)=-(x-y)²=-(

已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)因为(x-y)/(x+y)=3,则(x＋y)/(x－y)＝1/3则5(x-y)(x+y)-(x+y)/2(x-y)＝5*3-1/(3*2)=15-1/6=89/6

(x-4y)(2x+y)=：(x-4y)(2x+y)=2x^2+xy-8xy-4y^2=2x^2-7xy-4y^22x^2-8xy+xy-4y^2=2x^2-7xy-4y^2

(x+y)(2x-3y)=?（x+y）（2x-3y）=2x-3xy+2xy-3y=2x-xy-3y

x+y>=2,x-y由题意的x≥2-yx≤2+y∴2-y≤x≤2+y4-2y≤2x≤4+2y4-3y≤2x-y≤4+y∵0≤y≤3∴-3≤-y≤0-9≤-3y≤04≤4+y≤7-5≤4-3y≤4∴-5≤2x-y≤7-5≤m≤7

x+y>=2,x-y根据线性条件画出可行域,X+Y≥2,X-Y≤2,0≤Y≤3.画出可行域后,再画出直线2x-y=0然后平移,就可求得Z的最大值和最小值,m=2X-Y在y=3与x+y=2的交点（-1,3）处取得最小值为-5,在y=3与x-y

y'-2y=(e^x)-x首先求齐次方程通y'-2y=0特征方程：x-2=0x=2为特征根∴y=Ce^(2x)设方程的一个特解为y=Ae^x+ax+b代入方程：Ae^x+a-2Ae^x-2ax-2b=-Ae^x-2ax+a-2b=e^x-x

y'+2y/x=x通解

dy/dx=(2x*x*x*y-y*y*y*y)/(x*x*x*x-2x*y*y*y)(x*x*x*x-2x*y*y*y)dy=(2x*x*x*y-y*y*y*y)dx∫(x*x*x*x-2x*y*y*y)dy=∫(2x*x*x*y-y*y

已知X-Y/X+Y=3,求代数式2(x-y)/X+Y-3X+Y/X+Y已知X+Y分之X-Y等于3,求代数式X+Y分之2(x-y)减X+Y分之3X+YX+Y分之X-Y等于3x=-2yX+Y分之2(x-y)减X+Y分之3X+Y=(-x-3y)/

x²-(x-2y)(x+2y)+(x²-y)(y+x²)=?x²-(x²-4y²)+(x^4-y²)=4y²+x^4-y²=x^4-3y².

【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2=很累-3x-2y

（x-y)(x+y)-(x+y)^2+2y(y-x),其中x=1,y=3.（x-y)(x+y)-(x+y)²+2y(y-x)=(x+y)(x-y-x-y)+2y(y-x)=-2y(x+y)+2y(y-x)=2y(-x-y+y-x)