A. 
To find greater than or smaller than relation, we multiply the terms like (numerator of L.H.S with denominator of R.H.S and put the value on the left side. Then multiply the denominator of L.H.S with numerator of R.H.S and put the value on right side. Now compare the digits.)
So, solving A, we get 810<209 ... This is false
B. 
= 238>589 ..... This is false
C. 
= 496>780 .... This is false
D. 
= 420<660 ..... This is true
Hence, option D is true.
7n-4=31
7n=31-4
7n=27
n=27/7
:n=3
It’s equation and it’s really easy to solve
Answer: 34
Step-by-step explanation:
Substitute n with 9
-14+3(9-1)(2)
-14+3(8)(2)
= 34
Since C = 2rπ
if the C of earth = 25000 miles
then the r = C ÷ (2π)
= 25,000 miles ÷ 2π
= 12500 ÷ π
≈ 3978.87358 miles
Since radius is a measure of the distance from the center to any point on the circle then that distance would be about 3978.8736 miles<span />