If you have a Ti-84 series calculator, press "stat" then "Edit..." and then fill in the data table values for x and y in two lists. Then press "2nd" and "mode" to quit. Now press "stat" again and right arrow over to "calc" and press down until you find "ExpReg" and set the "Xlist" and "Ylist" that you used and you will get C as the answer. Another way to do this is to manually substitute values into all 4 equations, which is boring.
