Answer: 9x - 4
Step-by-step explanation:
We know that a number must be decreased by four. Let's break it up a little.
Nine times some number. We don't know what nine will be multiplied by, so we will just write a placeholder number: x. This number will be multiplied by nine. So it will turn into 9x.
We must decrease (subtract) from this by four. Subtracting 9x by four can be written as 9x - 4.
