Cylinder area=height times area of base (area of base=area of circle)
height =1.8
radius=6.1
area of circle=pi times r^2
area of circle=pi times 6.1^2=37.21π
times height
1.8 times 37.21π=66.978π
volume=66.978π ft^3
Not sure about the first one but the second one is option c (or -3). You just have to factor and find the solutions (so it would be -7 and 4 and then u just add them)
For question 39 the answer is c
Profit function - Cost function = Revenue function