Factoring two more equations
49x^2-100z^2
32t^2-50
I'll give you a few hints.
What number squared equals 49?
What number squared equals 100?
(?x + ?z)(?x - ?z)
Fill in the question marks and you should have your factors.
Factor out 2 on the second one to start. You should be able to take it from there. (It's similar to your first problem.)
I hope this will help get you started.