To solve any equation, we have to get the variables and the constants (numbers) on opposite sides of the equals sign.
First, we have to combine the like terms on the left side of the equation, resulting in
7a - 9 = 30
Then, because we want the constants on the right side of the equation, we have to +9 to cancel out the -9 on the left side.
7a=39
Next, the a has a coefficient of 7, which it is multiplied by. To undo multiplication, you have to divide. Therefore, we should divide both sides by 7.
a= 5 4/7 or 5.57142857143
In improper fraction form, a = 39/7, as this fraction cannot be simplified any farther.
<h2>
Answer:</h2>
Option: C is the correct answer.
C. 
<h2>
Step-by-step explanation:</h2>
The sequence is given by the explicit formula as:

where
is the nth term of the sequence.
Also, the first term of the sequence is: 
i.e.

Also,

Hence, the recursive formula which represents the same sequence is:
Option: C
I cannot answer that question because I need to equation
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