AR U. answered 10/20/19
Experienced Physics and Math Tutor [Edit]
The slope is nothing but the gradient (first derivative) of the curve.
Use implicit differentiation and the product rule.
(5/2)y3/2xdy/dx + y5/2 + x3/2dy/dx + (3/2)x1/2y = 0
grouping like terms and simplifying gives
dy/dx = (-3x1/2y - 2y5/2)/(5y3/2x + 2x3/2) plugging in the values of x, and y i.e. {x=16,y=1} gives the slope you want.