Answer:
The sequence above is a geometric sequence
For an nth in a geometric sequence

where n is the number of terms
a is the first term
r is the common ratio
From the question
a = 45
r = 15 / 45
The explicit formula for the sequence is
U(n) = 45(1/3)^n-1
Hope this helps you
The answer for this question is c.
we know that
The sum of the internal angles in the triangle must be
degrees
see the attached figure with letters to better understand the problem
Step 
<u>Find the measure of the angle x</u>
In the triangle ABC

solve for x



therefore
<u>the answer Part a) is</u>
the measure of angle x is 
Step 
<u>Find the measure of the angle z</u>
we know that
--------> by supplementary angles
substitute the value of x



therefore
<u>the answer Part b) is</u>
the measure of angle z is 
Step 
<u>Find the measure of the angle y</u>
In the triangle ACD

solve for y




therefore
<u>the answer Part c) is</u>
the measure of angle y is 
We know that imaginary roots always come in pairs, so we already know 4 solutions
-2, 2, 4 + i and a pair of 4 + i
Since imaginary roots always come in pairs we wont have more than 2 imaginary roots, since its a fifth degree root and we can only have 5 roots
So for sure, we will have 3 real roots and 2 imaginary roots
Last option, f(x) has three real roots and two imaginary roots
See the attached picture: