90+1.5x=y 100+2x=y y=?
[x(x-y)-y(x-y)+(x+y)(x-y)]÷2x其中x=2012 y=2013
已知X-Y/X+Y=3,求代数式2(x-y)/X+Y-3X+Y/X+Y
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
y'-2y=(e^x)-x
y'+2y/x=x通解
数学题已知p=x^/x-y-y^/x-y,q=(x+y)^-2Y(X+Y),
【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2=
y"-2y'+2y=x*(e^x)*cosx
x-y / 5y= (y-x)^2 / ( )
y=2x*arctan(y/x),求y‘’
y′=y/x+tan[(y/x)^2]
先化简再求值(x-y)(x+y)-(x-2y) 的完全平方+x(3x-5y)-(x-y)(x-2y),其中x=1/2 y