### Home > A2C > Chapter 7 > Lesson 7.1.2 > Problem 7-26

7-26.

Test his machines multiple times with different numbers.

Again, test several different numbers.

Input: *n*

machine 1: (*n*) + 2

output 1: *n* + 2

machine 2: (*n* + 2)^{2} − 4(*n* + 2)

output 2: *n*^{2} − 4

Look at the steps that the variable went through in part (c). Pay careful attention to what happens when it passes through the third machine.

Use the eTool below to test the machine.

Click the link at right for the full version of the eTool: A2C 7-26 HW eTool