y=(20+x)(80-2x) =-2x²+40x+1600怎么算

y=(x^2+x)/(x+1) 整数x,y满足方程2xy+x+y=83,则x+y怎么算 [x(x-y)-y(x-y)+(x+y)(x-y)]÷2x其中x=2012 y=2013 y=-(2x+3)/x^2求导怎么算? y=－x²-2x+3怎么解 y=(x+1)(x+2)的反函数怎么算 y= x/x-2的 导数 怎么算? x²-2x-x+2=0怎么算 x+y/2+x-y/3=6,4(x+y)-3(x-y)=-20 {(x+y)/2+(x-y)/3=6 4(x+y)-3(x-y)=-20 4(x+y)-3(x-y)=-20,2/x+y+3/x-y=6 (x+y)(x+2y)(x+3y)(x+4y)=-40