Answer:
18
Step-by-step explanation:
3+9=12
12/2=6
6x3=18
Divide through everything by <em>b</em> :

Since <em>a/b</em> < <em>c/d</em>, it follows that

Multiply through everything on the right side by <em>b/d</em> to get

and so (<em>a</em> + <em>c</em>)/(<em>b</em> + <em>d</em>) < <em>c/d</em>.
For the other side, you can do something similar and divide through everything by <em>d</em> :

and <em>a/b</em> < <em>c/d</em> tells us that

Then

and so (<em>a</em> + <em>c</em>)/(<em>b</em> + <em>d</em>) > <em>a/b</em>.
Then together we get the desired inequality.
I think it means grater or less ? Or positive or negative?
Answer:
It's the first option.
Step-by-step explanation:
It is turned down so the one half is negative (-1/2)
parabola will be in the form of a(x-h)^2 + k. (-h, k) is your vertex, in this case that is (15,25). so in the equation, you will have
-1/2(x-15)^2 + 25. first one.
Hope this helps!