The curve CCC has equation
5x+3y2+2xy2=12(3x)+15,y>0 5x + 3y^{2} + 2xy^{2} = 12(3^{x}) + 15, \quad y > 0 5x+3y2+2xy2=12(3x)+15,y>0Find an expression for dydx\frac{dy}{dx}dxdy in terms of xxx and yyy.
Curve CCC cuts the yyy-axis at the point PPP.
Find the exact value of the gradient of the tangent to CCC at PPP.