Call the region in the

-

plane, bounded by

and

,

. Then the volume under the given surface is
Expand
simplify 36 - 4.5x + 36 to -4.5x + 72
simplify 102 - 7.5x - 60 to -7.5x + 42
add 7.5x to both sides
simplify -4.5x + 72 + 7.5x to 3x + 72
subtract 72 from both sides
simplify 42 - 72 to -30
divide both sides by 3
simplify 30/3 to 10
Answer: x = -10
When solving this equation, you get the answer as -43.5.
To solve, we simply need to collect like-terms and then rearrange to get x on one side and numbers on the other:
(8x - 20) - 16 = 10x + 51
8x - 36 = 10x + 51
- 8x
-36 = 2x + 51
- 51
-87 = 2x
÷ 2
-43.5 = x
I hope this helps!