DE Solution Spaces Recall that the general solution of a DE means a family or set of

Question:

DE Solution Spaces Recall that the "general solution" of a DE means a family or set of solution functions (y | y satisfies the DE), where each y is a function on the interval determined by the domain of the DE. In Problems 1-3, does the general solution of each of the following DEs form a vector space or not? Explain
1. y' + 2u = et
2. y' + y2 = 0
3. y" + ty = 0