Is y= 2x (linear or nonlinear)

Can someone me and do the problem plz so i can understand it more better

True or false? a circle could be circumscribed about the quadrilateral below.

Which statements describe the solutions to the inequality x< -20 check all that apply. there are infinite solutions. each solution is negative. each solution is positive. the solutions are both positive and negative. the solutions contain only integer values. the solutions contain rational number values.