Answer:
*1 month later*
Step-by-step explanation:
Assume the parabola is placed on a graph where the x-axis is the top of the dish.
The vertex is then at (0,-30) The x-intercepts or zeros are at (-30,0) and (30,0)
The equation of such parabola would be:

Plug in vertex to find value of 'a'

Now find the focus given that


Answer: the microphone should be placed 7.5 inches from vertex.
Answer:
D) 4
Step-by-step explanation:
−9 + 12 + (unknown) + −8 = −1
<em>Start by going through and testing each option</em>
−9 + 12 + 2 + −8 =
3 + 2 + −8 =
5 + −8 =
−3
−3 ≠ −1
<em>A) 2 is not possible.</em>
−9 + 12 + −2 + −8 =
3 + −2 + −8 =
1 + −8 =
−7
−7 ≠ −1
<em>B) </em>−<em>2 is not possible.</em>
−9 + 12 + −4 + −8 =
3 + −4 + −8 =
−1 + −8 =
−9
−9 ≠ −1
<em>C) </em>−4<em> is not possible.</em>
<em>From this, D is looking like the answer. But to be sure, test it.</em>
−9 + 12 + 4 + −8 =
3 + 4 + −8 =
7 + −8 =
−1
−1 = −1
<em>D) 4 is the answer.</em>
B.) 85
They are alternate interior angles so they are the same degree.