A planet orbits a star with mass 4.35e+30 kg. The semimajor axis of the planet's orbit is 2.94×1012 m. What is the period of the planet's orbit in seconds?

An extrasolar planet has a small moon, which orbits the planet in 336 hours. The semimajor axis of the moon's orbit is 2.22e+9 m. What is the mass of the planet?

please help me i'm sooo confused about these problem.(Headbang)