Your answer is D. SSA Postulate because it doesn't exist!
The cotangent function is defined as the ratio between cosine and sine of a given angle, i.e.

Since you can't have zero at the denominator, the cotangent function is not defined when the sine is zero.
Let's look at your option:
, so the cotangent is defined here
, so the cotangent is not defined here
, so the cotangent is defined here
, so the cotangent is defined here
Answer:
4a^2 - 15b + 9b^2
Step by step explanation:
1345 - (-853) = D) 2198.
Simplify your brackets to get: 1345 + 853 and then add which will get you your answer, 2198.