Answer:

Step-by-step explanation:
To solve the question we refresh our knowledge of the quotient rule.
For a function f(x) express as a ratio of another functions u(x) and v(x) i.e
, the derivative is express as

from 
we assign u(x)=lnx and v(x)=x^2
and the derivatives
.
Note the expression used in determining the derivative of the logarithm function.it was obtain from the general expression of logarithm derivative i.e 
If we substitute values into the quotient expression we arrive at

125 = 5 * 5 * 5 = 5^3
Its a perfect cube.
Answer:
its A
Step-by-step explanation:
i literally just took the test
Answer:
Any letter you want
Step-by-step explanation:
The letters used for variables don't matter. What matters is what the variables represent: their numerical value. Variables are just to help identify what needs solving. Other common variables are a, b, and c which are found frequently in trigonometry. To answer your question, there are no "next letters." You can use any letter you'd like as a variable because it holds the same numerical value. Basically, the whole alphabet is at your disposal.