What the first order ODE, second order ODE tells us?

The perimeter of an equilateral triangle is 4 cm more than the perimeter of a square and the length of a side of the triangle is 8 cm more than the length of a side of the aware. find the length of a side of the equilateral triangle

What are the solutions of the equation x4 + 6x2 + 5 = 0? use u substitution to solve.

Joyce deposited $5000 in an account with an annual interest rate of 6%, compounded annually. how much money will be in the account 10 years later