Answer:
<h2>C.</h2>
Step-by-step explanation:
The equationof a circle:

<em>(h, k)</em><em> - center</em>
<em>r</em><em> - radius</em>
<em />
We have <em>center = (4, -1) → h = 4, k = -1</em>, and <em>r = 9</em>.
Substitute:

the answer would be
because you would need to find the LCD, which in this case would be 56 and you solve from there.
I think the answer is A.
It's probably wanting you to use pythagorean theorem.
Take into account, that in general, a cosine function of amplitude A, period T and vertical translation b, can be written as follow:

In the given case, you have:
A = 4
T = 3π/4
b = -3
By replacing you obtain:

Hence, the answer is:
f(x) = 4cos(8/3 x) - 3