The answer would be 15. The average of 6, 7, 8, 9, and 15 is 9. Hope this helps.
Answer:
A.
Step-by-step explanation:
Anwer A has the following equation:

In this equation, we can calculated the intercept replacing x by 0, as:

if this is the answer, the graph of g(x) should be through the point (0,-3) and that happens.
Additionally, the roots of the equations are calculated replacing g(x) by 0 and solving for x, so:

It means that the graph of g(x) should be through the points (2.236,0) and (-2.236,0) and that happens too.
So, the answer is A, 
Answer:
k = 9.
Step-by-step explanation:
2x + 3y -8=0
3y = -2x + 8
y = -2/3 x + 8/3
So the slope of this line is -2/3.
Therefore the slope of a line perpendicular to the above is -1 /-2/3
= 3/2.
kx - 6y = 9
6y = kx - 9
y = k/6x - 3/2
But the slope is 3/2,
So k/6 = 3/2
2k = 18
k = 9.