Question

http://prntscr.com/9h54gp

Answer 1

@Astrophysics

Answer 2

@Opcode

Answer 3

Try this websites to help you get the answer:
https://www.khanacademy.org/math/cc-eighth-grade-math/cc-8th-linear-equations-functions/linear-nonlinear-functions-tut/v/recognizing-linear-functions
https://www.khanacademy.org/math/cc-eighth-grade-math/cc-8th-linear-equations-functions/linear-nonlinear-functions-tut/e/linear-non-linear-functions

Answer 4

You could always graph it

Answer 5

You can plot the points here, click on table: https://www.desmos.com/calculator
Or you can use equation of a line definition what ever you're comfortable with

Answer 6

Theres many ways haha