For x3y2+y3x=-6, find dy/dx. I get an answer that is close to the right answer, but either my y is off by an exponent or something.

2. What answer do you get ?

3. -3x2y2-y3 / 3x2y+y3

$\displaystyle x^3y^2+y^3x=-6$

$\displaystyle 3x^2y^2+2x^3y y' +y^3+3xy^2 y'=0$

$\displaystyle \frac{dy}{dx} = -\frac{3x^2y+ y^2}{2x^3+3xy}$

5. Okay but why didnt you make it like -3x2y2-y3 / 2x3y+3xy2

6. ## Re.why

when numerator and denominator have common factor, we can simplify the quotient.