Math Review: FedEx Express

I generalized by using the equation to find volume. I used the format that I used to create my table for FedEx Express. First I chose a random pattern of numbers ranging from -10 to 25. And I labeled them as x. I made my x the same as the height of the box. Then to find my width, I used the formula 3(x) . Then I substituted x in the formula 3(x) and got my numbers for the width. After I found out the width. I had the numbers to find out what the length of my box is. Since I had the width and the height. Now I had to subtract the sum of the width and the height from the total which is 130. And I got my length. After I came up with my length, I went to find out my volume and then generalized it to make a function. I, then, plugged in the function into the calculator. Into the "y=" and press graph. Then after I pressed graph. A 3-dimensional line graph appeared and then I pressed 2nd..graph. And there was a table. I matched the table up with my written table. After that, I made a table. (My Y-maximum was 120,000, my Y-minimum was -120,000, my X-maximum was 36 and my X-minimum was -36) I plotted my points and noticed that each one of my group's calculations and graphing was nearly the same. Each one of them were 3-dimensional lines going the same way, just different vertex.