Algebra - A-REI.2 or A.REI.2
Solve simple rational and radical equations in one variable, and give examples showing how extraneous solutions may arise.
Solving radical equations. I'd so buy this if you would have made it for $1. I had trouble figuring out a real world explanation for "why do we need to learn this?" So I started brainstorming and came up with this idea.
I found real medicine and a real disease that needs a radical equation to calculate the dosage of medicine for a patient. Sure, I had to scaffold the lesson and I included all the pages of my instructional notes. I made a handout for you to use for them to practice. We finished in 3 days, but I think it could be done in 2.