# Solve 2x + y + y' x = 3y^2 y', why is this wrong?

2x+y+(dy/dx)x=3y^2(dy/dx)
This is wrong:
(dy/dx)(x-3y^2)=-2x-y
This is right:
2x+y=(3y^2-x)(dy/dx)

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This is wrong:
(dy/dx)(x-3y^2)=-2x-y
This is right:
2x+y=(3y^2-x)(dy/dx)

Those two equalities are actually the same, so I'm not sure "right" and "wrong" really apply.
The only difference is that the second is the negative of the first.
If you move each side of the first equality over the equals sign you will get the second

Defennder
Homework Helper
Yeah, scottie_000 is right. Multiply the first by -1 and you'll get the second.

So either answer would be correct in an exam?

Defennder
Homework Helper
Of course, if they were strictly equivalent and your teachers don't mind.