The first decimal point is tenth. 4.88
when rounding, we just look at the number right after the number you want to round to. it's 8 right? since 8 is closer to 10 than 0,
we round it to 4.9
(4.8 + 0.10)
Differentiating once, we have

Differentiating again,


as needed.
Plug the x value into the x value for your questions.
8.) -57
9.) -2
1.54-.10=1.44
Subtract the two to find your answer