Answer:
(4 x + 9) (16 x^2 - 36 x + 81)
Step-by-step explanation:
Factor the following:
64 x^3 + 729
64 x^3 + 729 = (4 x)^3 + 9^3:
(4 x)^3 + 9^3
Factor the sum of two cubes. (4 x)^3 + 9^3 = (4 x + 9) ((4 x)^2 - (4 x) 9 + 9^2):
(4 x + 9) ((4 x)^2 - 4 9 x + 9^2)
4×9 = 36:
(4 x + 9) ((4 x)^2 - 36 x + 9^2)
Multiply each exponent in 4 x by 2:
(4 x + 9) (4^2 x^2 - 36 x + 9^2)
4^2 = 16:
(4 x + 9) (16 x^2 - 36 x + 9^2)
9^2 = 81:
Answer: (4 x + 9) (16 x^2 - 36 x + 81)
The answer is B.
-9/3= -3, which means that each number is getting multiples by -3. Therefore, we can eliminate A and D. 27•-3=-81, so we can eliminate C. We are left with B, and we can check this by making sure that each number is correctly multiplied by -3.
Let t be time and r be rate, then if time varies inversely with the rate, the equation is

. If it takes 5 hours to drive a fixed distance at a rate of 80, we can sub those values in to solve for the constant of variation, k.

. Solve for k by multiplying 5 and 80 to get that k = 400. Now let's find a new time t when r is a rate of 70. We will use that k value to do this:

and find that it will take 20 hours to drive the distance at 70 mph when it takes 5 hours to drive the distance at 80 mph. Makes sense that it takes longer to drive a fixed distance when you are going slower.
It has to be D because A and B are incorrect and Angle A is not equal to B.