Hi there!
Below are the steps to solving the inequality, but there's not a lot.
1) Subtract 18 from both sides
7x + 18 - 18 > -3 - 18
7x > -21
2) Divide both sides by 7
7x/7 > -21/7
This gives you x > -3, so the correct answer is choice D.
If you're in doubt of this you can substitute the x > -3 for the x in the equation and see what you get. It's pretty simple.
Hope this helps!