The students at Cypress Middle School are selling rolls of gift wrap as a fundraiser. Each roll sells for $6.50 per roll. Which equation best represents y, the total cost of x rolls of gift wrap?

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).