You were right by taking the derivative. The equation you got was:

So for the point (3,5) you can use the equation we found from the derivative to calculate the slope at that point.

*substitute your slope from the derivative in for m

Then substitute this equation back into your original equation for y.

Get everything on one side and then find your x values either by factoring or quadratic formula.

This will give you two x values on the two tangent lines. You can simply plug each of these into your slope equation m = 2x and that will give your their slopes.

Using this info, see if you can work out the second one. Hope that helps!