1.2x-y+7=0 x+y=1 2.x-3y-10=0 y=x+5/3 的直线位置关系和交点坐标求过程

{6(x-y)-7(x+y)=21 {2(x-y)-5(x+y)=-1 x+2y=2x+y+1=7x-y 求：2x-y? 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 （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 x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 {(x+y)/2+(x-y)/3=1,(x+y)-5(x-y)=2.求x=?,y=? 先化简,再求值：y(x+y)+(x+y)(x-y)-x^2,其中x=-2,y=-1/2. 先化简,再求值:y(x+y)+(x+y)(x-y)-x²,其中x=-2,y=1/2. 设x大于1,y大于0,x^y+x^-y=2根号二,x^y-x^-y等于? 化简 x / y(x+y) - y / x(x+y) = 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}] 已知：2x+y=6,x-3y=1 求7y(x-3y)(x-3y)-2(3y-x)(3y-x) x(x+y)(x-y)-y(y+x)(y-x)=(x-y)( )填空 7x:4y,x:y=( ):( x>=1,x-y y=x-1(x y'-(1/x)y=xe^-x