Question

A classmate wrote the solution to the inequality |-4x + 1| > 3 as show below. Describe and correct the error.

Answer 1

Answer:

See below.

Step-by-step explanation:

The last step is incorrect. When we divide both sides by a negative the inequality is flipped. The answer is x < -1/2.

Also they  omitted  the other possibility that the expression in the vertical lines could be negative.

We also have the inequality

- 4x + 1 < - 3

-4x < -4

x > 1.