Idon’t understand part b. can someone me? ! picture included

What we want to do here is make it long division. x²+2x+8 on the left, and +x³+7x²-6x+8 on the right, as will be shown

            x²
             ________________________________________
x²+2x+8| +x³+7x²-6x+8

We start off by dividing by x², which is x². After that, we put x² at the top and subtract (x²+2x+8)*(x²) from the whole equation, which looks like 

                 x²
             ________________________________________
x²+2x+8| +x³+7x²-6x+8
             - (+2x³+8x²)
               _____________________
                               -x³-x²-6x+8. Continue this pattern until you can't (the next step would be dividing (-x³ by x²) and you should have your answer! Good luck, and feel free to ask any questions as necessary!