What is true about Marcus’s work? Check all that apply. Marcus should have substituted –10 for b, not 10. The denominator should be 1, not 2. Marcus should have subtracted 4(1)(25) in the square root. This equation, when solved correctly, only has 1 real number solution. This equation has 2 real number solutions.

Amass weighing 16 pounds stretches a spring 8/3 feet. the mass is initially released from rest from a point 2 feet below the equilibrium position, and the subsequent motion takes place in a medium that offers a damping force that is numerically equal to 1/2 the instantaneous velocity. find the equation of motion if the mass is driven by an external force equal to f(t)=cos(2t).