Use the polynomial division to determine if x = -5 is a root of the function f(x) = 5 x 3 + 29x^2 +19x -5

also what is another way, other then polynomial division, that you could tell if -5 is a root of f(x)?

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).