Answer:
9.07 and 7.77 respectively.
Step-by-step explanation:
To determine the upper control limit, add 0.65 lb to 8.42 lb, obtaining 9.07 lb.
To determine the lower one, subtract 0.65 lb from 8.42 lb, obtaining 7.77 lb.
Subtract 2x from both sides then you’d have -7x+4=16 Then you subtract 4 from both sides and you’d get -7x=12. Next you divide both side by -7 so x=1.75 rounded to the nearest hundredth.
Each term differs by -68 and the first term is -68, we have:

As an expession it's just -68n.