Every stage of the argument broken out, marked as you go, with the reason. What you can see is separated from what it means, and the working columns are shown to you.
The number on the end of Δy ÷ Δx is almost never the answer. It’s 4π² over g, or one over the spring constant, or the resistance itself, and which of those it is depends on what you put up the page.
At least six problems, then the ones you missed again. Your place is saved.