Does this curved line represent a function? If not, at what points does it fail the vertical line test?

For the sequence [tex]a_{n} = 2n/(n+1)[/tex], what is the value of [tex]a_{10}[/tex]

Write the equation of the line that passes through (3, 4) and (2, −1) in slope-intercept form. (2 points) y = 3x − 7 y = 3x − 5 y = 5x − 11 y = 5x − 9

Find the value of x. also give me an explanation so i can complete it to other questions as well, : )