Answer:
2x squared +1 (-)x squared -7 is
a.) x squared +8
Step-by-step explanation:
:)
For this case we have to, by definition:

This means that the tangent of angle B will be equal to the leg opposite the angle on the leg adjacent to the same angle.
Then, clearing to have:

Rounding out the value of a we have:

Answer:
Option C
I think it is a Convience Sampling.