https://www.amazon.com/CliffsNotes-Praxis-Mathematics-Content-Knowledge/dp/0544628268/ref=sr_1_2?ie=UTF8&qid=1536453143&sr=8-2&keywords=praxis+5161 try this. Go through Khan Academy on areas you're weak in for a quick refresher. There are plenty of youtube videos on specific problems in regards to praxis 5161. YOU CAN DO THIS! good luck!
Khan Academy has good free resources for both matricies and calculus.
https://www.khanacademy.org/math/precalculus/precalc-matrices
https://www.khanacademy.org/math/calculus-home
Other than that, there are a bunch of books on amazon. This one is pretty cheap, and it probably fine.
https://www.amazon.com/CliffsNotes-Praxis-Mathematics-Content-Knowledge/dp/0544628268/ref=sr_1_1?ie=UTF8&qid=1477581444&sr=8-1&keywords=math+praxis+5161
I would suggest against the mometrix materials. They tend to be pretty sloppily written.