Rachel says the answer is 90degrees but Ross says there is no way to tell because no other angles are given who is correct ? Explain how you know. PLEASE HELPPP I HAVE A D

Answer this 30 points and brainliest!

Lance lived in portugal and brazil for a total of 14 months to learn portuguese. he learned an average of 130 new words per month when he lived in portugal, and an average of 150 new words per month when he lived in brazil. in total he learned 1920 new words. write a system of equations to represent the situation. use x to represent portugal, and y to represent brazil

F(n + 1) = f(n) – 8. if f(1) = 100, what is f(6)?