0.2x-0.5y=0,5(x+1)-3(y+17)=-27不要复制

（x+y-5)*（x+y-5)+（x-y+3)=0 x*x-y*y 已知:3x-5y=0,求x/y,x-y/y,x-y/x 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 {x+y=1 ,xy=-6{x(2x-3)=0,y=x²-1{(3x+4y-3)(3x+4y+3)=0,3x+2y=5{(x-y+2)(x+y)=0,x²+y²=8{(x+y)((x+y-1)=0,(x-y)(x-y-1)=0 0.2x-0.5y=0,5(x+1)-3(y+17)=-27不要复制 解方程组：①4x+3y-5=0,x-2y-4=0.②5x-2=2（y-1）,2（x-2）+（y-1）③0.2x+0.5y=0.2,0.4x+0.1y=0.4④3x-13y=-12,x+3y=2 (x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5) 解下列方程组：{x(2x-3)=0,y=x²-1{(3x+4y-3)(3x+4y+3)=0,3x+2y=5{(x-y+2)(x+y)=0,x²+y²=8{(x+y)((x+y-1)=0,(x-y)(x-y-1)=0 解方程组：（0.2x+0.1y）/2- （4x-y）/10=（x-y）/5+ (3x+0.5y)/30 (3x+2y-1)/8=3-(0.8x-5y)/41=-= 方程组x²-y²-3x+5y=0,x-y-1=0 3x+4y-5=0 x^2+y^2=1求x.y x1:4x-3y=8;y=7-5x;2:2x-7y=8,3x-8y-10=0;3:4x-y=-1;4:5x-10y+15=0;5:2x-4y=6,3x+2y=27;6:3y=x+5,2x+5y=231：2x+3y=7,3x-5y=1;2:3x+5y=5,3x-4y=23;3:3x+5y=5,3x-4y=23;4:5x+y=7,3x-y=1;5:4x-3y=5,4x+6y=14;6:6x+7y=5,6x-7y=19;7:0.5x-3y=-1,-二分之一x+5y=3 高数求极限 y=[(3^x +4^x +5^x)/3]^(1/x) (x->0) 已知|3x+y-0.5|+(x+2y+1.5)^2=0,求代数式（x-y)(x-2y)-3x(1/3x-y)+(2x+y)(2x-y) 快. mathematica软件,已知y[x],Y=f1(x),X(x)=f2(x),如何plot Y[X]?y[x_] := x + 9.81/2*x*xk=1X[x] = x - k*y'[x]/(1 + (y'[x])^2)^0.5Y[x] = y[x] + k/(1 + (y'[x])^2)^0.5Plot[{y[x],Y[X],},{x,0,2}] {(x+y)/2+(x-y)/3=1,(x+y)-5(x-y)=2.求x=?,y=? 若x^5+x^4y+x^4+x+y+1=0,且3x+2y=1,求x,y的值 合并同类项,3x^2-[7x-(4x-3)-2x^2] 光求值：1/2x-2(x-1/3y^2)+(-3/2x+1/3y^2)其中x=-2,y=2/3 .3y^4-4x^3y+0.2x^2y^2-4y^4+0.5x^3y-1/5x^2y^2其中x=-2,y=0.3