![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/step1.JPG\")
Observe the table, define the x coordinate is depth (km), and y coordinate is temperature(oC).
\The difference of the x values is 1, and the difference of the y values is 35.
\The difference in y values is 35 times x plus 20.
\Then the equation of the function f (x) = y = 35x + 20.![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/solution.JPG\")
The solution of the equation is y = 35x + 20.