A sample of 20 human resource managers is takenand annual salaries are reported. What is theprobability that the sample mean annual salaryfalls between $70,000 and $80,000?

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

I'll give brainliest if you answer right : )

Which function has the domain x> -11