just need help with problem 2.... finished problem 3.

I tried using summation of moments = 0 at point O to get effective stiffness but it doesnt work cause it cancels out

Why did they use the graphic for a resistor where they mean spring?

i can solve em vs fgsssss

spring and resistor is the same graphic lol

This.

Looks like you need to find the second order ODE based on x(t) = cos(wt + delta) where w = (k/m)^1/2... I remember doing a similar problem with masses' suspended on several springs in my DE class, I believe each spring will have it's own respective equation in terms of omega, m, and k and you'll need to set up a 3x3 matrix and apply cramers rule to solve for each variable.