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 :)