I please solve and explain

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

Multiply −2x(6x^4−7x^2+x−5) express the answer in standard form. enter your answer in the box.

The number of revolutions of two pulleys is inversely proportional to their diameters. if a 24-inch diameter pulley making 400 revolutions per minute is belted to an 8-inch diameter pulley, find the number of revolutions per minute of the smaller pulley.