Is the algebra, if so what type?
Use a calculator bruhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh
Must it be a scatterplot or no?
Answer: - x - 120
Explanation: You want to find the opposite of (120-x) not just x, so you just put the negative symbol next to both the variables.
((X1+x2)/2,(y1+y2)/2)
---> ((2+2)/2,(1+4)/2)
---> (2,2.5)