Question

I need help with 7 and 8 it ask If it's a right triangle

Answer 1

They are both not right angles. You can easily tell because you can't draw a square in the corner.

Answer 2

If you know the law of sines and cosines, you will realize that not every triangle is a right triangle. If all of the three angles add up to 180, then you would say that it is a right triangle. Here is a sheet that you can use if you know sines and cosines law.