x=1.5y+40 y=1/2x+20如何算啊?在这里说声谢谢！

1x=0.5y 2x=2y 3x=4.5y 求规律.（如y＝...）如果y是1.5,x是多少? x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 已知正数x,y满足2x+5y=20,求1/x+1/y的最小值如题 如何用matlab解非线性方程组,求写成程序,万分感激!E1=-1/2/(betainc(1-y/x,1.5,y+1)+(y/x).^y*exp(x-y)*sqrt(1-y/x)*exp(y-x)/x+(y/x).^y*exp(x-y)*sqrt(pi)/2/x>^1.5*erfc(sqrt(x-y)))*(2/z.^2+1/k.^2)*(2/3*y*((y-2)*0.5*betainc(1-y/x,0.5,y-1)-( [3x^2-(x+y)(y-x)][2(-x-y)(y-x)+2x^2+3y^2],其中x=-2分之1,y=1.5 如题 如果x-3y/x=1/2,那么x/y= 请问这样的方程组又如何用matlab求解呀?式子：[x,y,z]=solve('(2*x+3*y+z)^2*(x+y)*(1-z)/((1-x-y)*(2-0.5*x)^0.5*(1+3+1.5*x+2*y)^1.5)=3.46e+11','(2*x+3*y+z)^3*(x+y)*(1-z)/((1-x-y)*(1-y-z)^0.5*(1+3+1.5*x+2*y)^2)=0.966','(2*x+3*y+z)*(x+y)*z （x-y)(x+y)-(x+y)^2+2y(y-x),其中x=1,y=3. 2y(x+二分之一y)-[(x+y)(x-y)+2y(y+x)],其中|x-1|=2 (x+y)(x-y)-(x-y)^2如题 (x+y)(x-y)-(x-y)^2 已知x+y=a,2x-y=-2a,求[（x/y-y/x)/(x+y)-x(1/x-1/y)]/[(x+1)/y]的值 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 如题{(X,Y)|(X+2)2+|Y-3|=0,X,Y属于R}= 如题{(X,Y)|(X+2)²+|Y-3|=0,X,Y属于R}= 如何用matlab画 z=(x-40)/(x^2+y^2-x-y-4)+1/((4*y-3*x)^2+4); x+y/3+x-y/2=6 4(x+y)-2(x-y)=40 已知(2x+2y+1)(2x+2y-1)=3 则x+y=___如题 x+y/2+x-y/3=6,4(x+y)-3(x-y)=-20