Plz help me im stuck on this question, Derek has 2 balls he gave 2 away how many does he have left

Need ! give step by step solutions on how to solve number one \frac{9-2\sqrt{3} }{12+\sqrt{3} } number two x+4=\sqrt{13x-20} number three (domain and range) f(x)=2\sqrt[3]{x} +1

The holiday party will cost $160 if 8 people attend. if there are 40 people who attend the party, how much will the holiday party cost

Plzzz answer both questions and i will give you 100 points