Please sir solve question no.(IV) & (v). I am not satisfied With my solution as it seems wrong with respect to me

The area of a square field is 640000cm2.what is its area in hectares

Please solve this integration. I am facing difficulty in it How to solve this. Please solve anyone. Humble request

Using laplace transform, solve d2y/dt2 + dy/dt = t2 +2t given that y=4 and y’=-2 and t=0

how to solve this?this is interger type question .