Which expression is equivalent to -6.5c-5.1+2.3c-1.8

If 1 km = 0.621 miles, how many miles are in a centimeter

Which expression calculates the speed in meters per second of an object that travels a distance of 100 m every 20 seconds

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