Using implicit differentiation on each term:
y2e2x + xy3 - 1= 0
The first term is the product rule d/dx f g = f g' + f' g
so the first is y2 and the second is e2x. You must also use the chain rule.
So its derivative with respect to x is
y2 ( e2x(2)) + 2 y y' (e2x)
The second term is also a product rule.
x (3y2 y') + (1) (y3)
The third term is a constant so its derivative is 0.
Putting the pieces together
y2 ( e2x(2)) + 2 y y' (e2x) + x (3y2 y') + (1) (y3) + 0 = 0
Now clean up each term .
2y2e2x + 2 y e2x y' + 3 x y2 y' + y3 = 0
Now put the terms that do NOT contain a y' on the right side of the =
2 y e2x y' + 3 x y2 y' = -2y2e2x - y3
Now factor the y' on the left side. Then divide. Then simplify.