The perimeter of an equilateral triangle is 24x- 12. How can you write an expression to represent its perimeter as a sum? A.6x+3+6x+3+6x+3 B.24x-6+6 C. 8x-4+8x-4+8x-4 D.6x+4x+12

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).