Circle the step where the error has occurred. Explain why it is an error.

The step where the error occurred is Step 4. After step 3, 34x should've been added to both sides of the equation. Instead of -17x, Step 4 should say 17x, because -17+34=17. Somehow, the whole number in Step 4 also changes from 40 to 14. Nothing changed it, it should still be 40. Step 4 should be: 17x=40.
To continue solving, divide both sides by 17.
x should be 40/17 or 2 6/17.
I hope this helps :)