54
a rule I follow:
same signs positive,
different signs negative.
-9 * -3 = 27
27 + 27 = 54
Answer:

a=8.182 and b=8
Step-by-step explanation:
Weight of the Empire State Building =
pounds.
Weight of the One World Trade Center building= 88,200,000 pounds.
=
The addition of the two:

Comparing with the form: 
a=8.182 and b=8
Answer:
V = 267.9 in^3
Step-by-step explanation:
V = 4/3 * (pi) * r^3
V = 4/3 * 3.14 * 4^3
V = 4/3 * 3.14 * 64
V = 256/3 * 3.14
V = 803.84/3