If f4y 3 = 6y + 9, what is the value of 7y?

How do i simply this expression (quadratic formula basis) on a ti-84 or normal calculator?

What is the radius of a circle with an area of 78.5 cubic inches? use 3.14 for pie

Isabel graphed the following system of equations. 2x – y = 6 y = -3x + 4 she came up with the solution (2,-2). what were the 3 steps she did to get that solution? (make sure they are in the correct order)