We have:

and:

so:


It is a finite sum, so it is convergent.
The radius is half the diameter, so the formula would be r=d divided by 2
Given problem is 
To simplify that we need to multiply and divide by conjugate of the denominator
conjugate of denominator 6+i will be 6-i as we just need to change sign of the imaginary part
Now multiply and divide by 6-i







Hence final answer is 
The first thing you should observe in the graph is that
6x + 4y = 24 is a line with a negative slope.
2x-4y = -8 is a line with positive slope.
After you identify the functions you can choose the correct affirmations.
The x-coordinate of the solution is 2. The y-coordinate of the solution is 3. The ordered pair that is the solution to the system lies in Quadrant I.
The answer to this would be 3y + 5