0.58=(0.5x+0.7y)/(x+y)求X比y怎么求

0.58=(0.5x+0.7y)/(x+y)求X比y怎么求 老师.0.58=(0.5x+0.7y)/(x+y)求X比y怎么求 0.5x+0.7y=35,x+0.4y=40.求x=?,y=? 已知X,Y独立,P(x)=0.5,p(x+y)=0.7,求p(y). x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 化简 x / y(x+y) - y / x(x+y) = y=x(x 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+3y)²-2（x-y)（x+y)+(x+y)²其x=0.5,y=-2 x(x+y)(x-y)-y(y+x)(y-x)=(x-y)( )填空 x+x+x+x+y+y+y=56 A={（x,y)|y>=0.5|x-2|},B={(x,y)|y matlab画二元函数图像z = (x/(x+y) + 1.96*1.96/(2*(x+y)) - 1.96 * ((x/(x+y)*(1-x/(x+y))+1.96*1.96/(4*(x+y)))/(x+y))^0.5)/(1+1.96*1.96/(x+y))该怎么画 已知x+y=-4试计算多项式0.5(x+y)+4(x-y)-3(x-y)-1.5(x+y)-x+y的值 解方程组 0.2X+0.3y=4.6 0.7x-.5y=.6解方程组 0.2X+0.3y=4.6 0.7x-0.5y=0.6 『4x+9y=97 5x+5y=65』『0.2x+0.3y=4.6 0.7x-0.5y=0.6』 0.2X^2Y-0.5XY^2-0.3X^2Y+0.7X^2Y,当x=-1,y=2/3时,最后=? y={x+[x+(x)^0.5]^0.5}^0.5求导