Can someone please help

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.

Of four points are collinear, they are also coplanar

To solve the system of equations below, grace isolated the variable y in the first equation and then substituted into the second equation. what was the resulting equation? 3y=12x x^2/4+y^2/9=1