So the expression is:

You can combine like terms, which are terms that contain the same variables raised to the same power. That means you can combine the two

.

The other terms can't be combined.
Your final answer should be

.
It’s 9.9 because 3 times 3.3 is 9.9
The answer is -125x^6
You do
(-5)^3 * (x^2)^3
Volume of sphere is given by:
V=4/3πr³
the radius of the sphere will therefore be given by:
5000π=4/3πr³
solving for r we get:
r³=3750
hence
r=15.54 m
the area will therefore be:
A=4πr²
A=4π(15.54)²A=965.49π m²