Answer:
D. The correct value of c = 7.4
Step-by-step explanation:
According to Tangent-Secant theorem:
"When a tangent and a secant are drawn from one single external point to a circle, square of the length of tangent segment must be equal to the product of lengths of whole secant segment and the exterior portion of secant segment."
Here, the external length of tangent segment = 10
Also, the length of internal segment is 14 and c.
So, by the SECANT THEOREM:
or, c = 7. 1428
Now, rounding off the value of c = 7. 14 to the nearest tenth, we get
c = 7. 4
Hence the correct value of c = 7.4
It’s hard to tell due to no labels, but these are your angles due to the equal angles theorem and a few other theorems. Hopefully with this image you can hopefully find your answer. You may need to add angles together depending on what you are looking for. And possible even figure out what angle measure would make a (180 degree) triangle.
Hope this helped
The answer to the question
The correct answer is the first option.
If you want to use elimination, you can sum the two equations for example, so that the x's simplify:
Plug this value for y in one of the equations to derive the value of x:
So, the solution is 
The external angle is equal to the sum of the opposite internal angles.
.. 6x +1 = (2x +10) +79
.. 4x = 88 . . . . . . . . . . . . . subtract 2x+1
.. x = 22
