Need help please you only have to answer the last two

Find dy/dx using implicit differentiation ln(20+e^xy)=y

The serenity and the mystic are sail boats. the serenity and the mystic start at the same point and travel away from each other in opposite directions. the serenity travels at 16 mph and the mystic travels at 19 mph. how far apart will they be in 3 hours?

How many solutions does the nonlinear system of equations graphed below have? a. one b. zero c. four d. two