2(9n - 6) + 52 = 2(7n + 8)

Step-by-step explanation:

2×9n=18n

2×-6=-12

52-12+18n= 38 +18n

2×7n=14n

8×2=16

14n+16

38+18n=14n+16

subtract 14n from 14n and 18n

38+4n=16

subtract 38 from 38 and 16

4n=-22

divide each side by 4

n= -5.5

No, he made a mistake solving for the volume of both figures.

Step-by-step explanation:

You can just look at the formula and see it

Volume of a square pyramid : V=1/3bh , he forgot to use the 1/3. Volume of a cylinder: πr^2h , he forgot the π