On dawgs this is so true lol

The sum of two numbers is 86, and their difference is 20. find the two numbers

What is the value of f(x) = 2.2 for f(-2)?

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).