Question

How do you solve `|7x - 15|<20`?

Answer 1

`-5/7 < x < 5`

Explanation:

You have `|x|<\alpha \iff -alpha < x < \alpha`

So,

`|7x-15|<20 \iff -20<7x-15<20`

`\iff -5 < 7x < 35`

`\iff -5/7 < x < 5`