Solve this system by using substitution:
y=7x-10
y=-3

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.

Which representation has a constant of variation of -2.5

How can you tell when x and y are not directly proportional?