The given question is 8+13+18+...... which is in arithmetic progression . And for arithmetic series, we have to use the following formula for nth term .

Here a =8 , d=5
So we get

And the required expression for n=7 is

Hello,
Here is your answer:
The proper answer to your question is..... 200,000=4x-20
When your doing questions like these make sure you pay attention to the question.
Your answer is 200,000=4x-20
If you need anymore help feel free to ask me!
Hope this helps!