Look at number 17. what did i do wrong?

When you are checking your answers, your formula should read out as 9(2.222) - 8 = 12, which is simply filing in the x value that you calculated (it comes out to 11.998 which is correct). You wrote it out as 9(2.22) - 8 = -6, which is why your checking process was incorrect 

The answer is nothing you done nothing wrong I wish you a happy even8ng bye