Solve for r 12r - 8 = -32

Add 8 to both sides
12r -8 +8=-32 + 8
12r=-24

Divide by 12
12r/12=-24/12
R=-2

12r-8=-32 add eight to both sides
     +8  +8
12r=-24 divide 12 from both sides
12/    12/
r=-2
hope this helps

The formula for cylinder of pi is v = π r ^ 2 h.

So you are going to do pi x 6^2 x 12 = 1357.168026350791 then divide 1357.168026350791 by pi and you get C. 432 pi in.^2

Also here is a link to a calculator that can really help with problems like this.
https://www.eeweb.com/tools/calculator

Hope this Helps!!