Find the solution to mx''+cx'+kx=f(t), x(0)=0, x'(0)=0 for an arbitrary function f(t), where m> 0, c> 0, k> 0, and c^2-4km> 0 (system is overdamped). write the solution as a definite integral.

There are a total sales of 2,000 dollars on monday on tuesday sales dropped 10% on wednesday sales dropped another 20% compared with tuesday from wednesday to thursday sales increases by an equal amount to 25% of monday total sales what is the net change in dollars on total sales from monday to tuesday