Step-by-step explanation:
part A:

part B:
![Area_{_{surface}}=3.14*(15+9)=3.14*24=75.36[units^2].](https://tex.z-dn.net/?f=Area_%7B_%7Bsurface%7D%7D%3D3.14%2A%2815%2B9%29%3D3.14%2A24%3D75.36%5Bunits%5E2%5D.)
A+5=5a+5 Subtract a from each side
5=5a+5 Subtract 5 from each side
0=5a Divide each side by the number before the variable to get it alone.
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5 5
a=0
Five hundred ninety two thousand six hundred eighty two
8 x 6 = 42 add two zeros so 4200