Answer: 
Step-by-step explanation:
You can find the value of "c" that will make it a perfect square trinomial by Completing the square.
Given the following expression provided in the exercise:

You can notice that it is written in this form:

Then, you can identify that the coefficient "b" is:

Since to complete the square you must add and subtract the half of square of coefficient "b", you can conclude that:

Therefore, substituting "b" into
, you get:

The correct answer is "His teacher advised it because he did not have time to tutor Euler privately." I just did the assignment and got it correct.
Answer:
-6.2, -3.1, -1.55, -0.775, -0.3875...this is not an arithmetic sequence
Step-by-step explanation: