I am assuming the ones that are not circled are not due, so I can help with one of those. Let's look at problem 35.
Let's read what is happening. On the left-hand side (LHS) of the equation, you have . On the right-hand side (RHS), you have times an expression containing . We want to isolate the expression containing . We want that coefficient to be 1. So, we divide both sides by 4a:
We still want to get alone. Currently, on the LHS of the equation, we don't have any terms with , but on the RHS, we have plus some term that does not contain any . So, we subtract from both sides of the equation:
Now we are done. We have on one side of the equation and everything that does not have an on the other.