Question

A description of what Derek did wrong and what he should have done instead the correct solution graphed on a number line

Answer 1

Derek did it wrong that he did not change the inequality sign while dividing both side terms of the inequality by - 3.

Explanation:

We are going to solve an equation of inequality of single variable x.

We will start with, -3x + 5 > 20

⇒ -3x + 5 - 5 > 20 - 5

⇒ - 3x > 15

⇒
`(-3x)/(-3) < (15)/(-3)`

⇒ x < - 5

Therefore, while dividing both side terms by -3, the inequality sign will change from > to < sign.

So, Derek did it wrong that he did not change the inequality sign while dividing both side terms of the inequality by a negative number. (Answer)