A student showed the steps below while solving the inequality Ix-4I <= 1by graphing.
Step 1: Write a system of equations y1 = Ix-4I<= 1
Step 2: Graph the two equations:
graph picture
Step 3: Identify the values of x for which y1 <= y2: X=3 or x=5
Step 4: Write the solution in interval notion:
(-infinity, 3)u(5, infinity)

What is the first step in which the student made an error?

THE ANSWER IS:
Step 3, because the value for x for which y1 <= y2 also include values between 3 and 5.