Answer:
The given fraction
reduces to 
Step-by-step explanation:
Consider the given fraction 
We have to reduce the fraction to the lowest terms.
Consider numerator 
We can take x² common from both the term,
Thus, numerator can be written as
Given expression can be rewritten as ,

We can now cancel
from both numerator and denominator,


Thus, the given fraction
reduces to 
Answer:
1
Step-by-step explanation:
7 + 2x = 9
Carry over the 7 to the 9.
2x = 9-7
2x= 2
x = 2÷2
x = 1
Answer:
Volume = 35185.8 
Step-by-step explanation:
Recall the formula for the volume of a cone: 
Where R is the radius of the cone's circular base (in your case half of 80 km,(that is 40 km)
And h stands for the height of the cone (in your case 21 km)
We replace such in the formula and calculate its final value:

We round it to the number of decimals your problem request (let's say to one decimal) and also include the cubic units:
Volume = 35185.8 