Factor out 12t to get 12t(9t-5)
You need to add them all up
Answer:
.
Step-by-step explanation:
I graphed the region in the image below. The blue line is y=3, the purple line is x=1 and the green curve is y =
. The shaded region in blue is the region we are going to rotate.
Now, to find the volume v=
where a=1, b=3 (left and right points of the region), p(x) is the distance from the rotation axis to the diferential Δx, we say p(x)=x and h(x) is the height of the region, in this case is h(x)=
. Then,
v = 
= 
= 
= 
= 
=
.
B.25
sorry if my writing is not clear