Seven less than a number 15

When the solutions to each of the two equations below are graphed in the xy-coordinate plane, the graphs of the solutions intersect at two places. write the y-cordninates of the points of intersection in the boxes below in order from smallest to largest. y=2x y=x^2-3

Which representation has a constant of variation of -2.5

Find the center and the radius of the circle with the equation: x^2-2x+y^2+4y+1=0?