a car uses 57 liters of gasoline for every 644 kilometers traveled. it takes 8 hours to use all the gasoline in the tank. what is the average speed of the car during the trip?

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

What are the solutions of the system? solve by graphing. y = -x^2 -6x - 7 y = 2

White shapes and black shapes are used in a game. some of the shapes are circles. while the rest are squares. the ratio of the number of white shapes to the number of black shapes is 5: 11. the ratio of the number of white cicrles to the number of white squares is 3: 7. the ratio of the number of black circles to the number of black squres is 3: 8. work out what fraction of all the shapes are circles.