What statement describe the expression 18+1/2×(9-4)

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

If you could answer these your a life saver

8litres of paint can cover 129.6 m². how much paint is required to paint an area of 243m²?