The explanatory variable is the amount of exposure the student is given to classical music.
Solution given in the attachment.
Answer:
EF×AB= DF×AC
6×12=9×8
72=72
A is the correct answer also the angle in the diagram too.
Answer:
x = 14 is an extraneous solution
Step-by-step explanation:

Divide both sides by 4.

Square both sides.



Since we squared both sides, we much check for extraneous solutions because the process of squaring both sides can introduce extraneous solutions.
Check x = 14:





16 = -16 is a false statement, so the solution we found, x = 14, is an extraneous solution.