7x²=28 i'm not sure about how to do thus problem

If there is no real number solution to the quadratic equation x^2+2x+c=0 what is a possible value of c? 1 -2 0 3

The average number of vehicles waiting in line to enter a parking lot can be modeled by the function f left parenthesis x right x squared over 2 left parenthesis 1 minus x right parenthesis endfraction , where x is a number between 0 and 1 known as the traffic intensity. find the rate of change of the number of vehicles waiting with respect to the traffic intensity for the intensities (a) xequals0.3 and (b) xequals0.6.

Through non-collinear points there is exactly one plane.