11 hours. The temp. decreases with time at a 2:1 ratio receptively <span />
Answer:




With 



So then the x intercept would be (0,-5). And finally we can graph the function as we can see in the figure attached.
Step-by-step explanation:
For this case we know the following function:

We can begin the zeros or the values where the function is 0 like this:

And solving for x we got:

Now we can rewrite the expression like this:

And we can find the position for the vertex at x with this formula:

With 
And replacing we got:

And then with the coordinate of x for the vertex we can find the coordinate of y replacing the value of x obtained for the vertex.

Then we can find the intercept using the value of x=0 and replacing into the function we got:

So then the x intercept would be (0,-5). And finally we can graph the function as we can see in the figure attached.
Don't forget the invisble negative ones to distriute
do inside to outside
{n-1-1[n-1-1(n-1)]}
do inside
{n-1-1[n-1-n+1]}
simplify inner parenthasees
{n-1-1[n-n+1-1]}
{n-1-1[0]}
multply
{n-1-0}
add
n-1-0=n-1
it is n-1 simplified
I think it's "B" because it the distance between them