Please help me with the following. I am always confused with Euler's method. The tank problems also confuse me, especially setting up equations and solving them.

4. (20 points) Consider the initial value problem y' =x+ 2y?, y(0) = 1. (a) (8 points) Use one step of Euler's Method to approximate the solution at x =1. (b) (12 points) Use two steps of Euler's Method to approximate the solution at x= 1. 5. (20 points) Pure water flows at a constant rate of 2 L/ min into a large tank that initially held 100 L of brine solution containing 4 kg of salt. The solution inside the tank is kept well stirred and flows out of the tank at a rate of 3 L/min. (a) (5 points) How much solution is in the tank at time t minutes? (b) (15 points) Determine the mass of salt in the tank at time t