SOLUTION: 10. Consider f(x) = x^2+qx+r. The graph of f has a minimum value when x= -1.5. The distance between the two zeros of f is 9. a. Show that the two zeros of f is 9. b. Find the

Algebra ->  Functions -> SOLUTION: 10. Consider f(x) = x^2+qx+r. The graph of f has a minimum value when x= -1.5. The distance between the two zeros of f is 9. a. Show that the two zeros of f is 9. b. Find the      Log On


   



Question 1104204: 10. Consider f(x) = x^2+qx+r. The graph of f has a minimum value when x= -1.5.
The distance between the two zeros of f is 9.
a. Show that the two zeros of f is 9.
b. Find the value of q and of r.

Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


If the function has a minimum value when x=-1.5, then x=-1.5 is the axis of symmetry.
Then if the distance between the two zeros is 9, the two zeros are 9/2=4.5 units either side of the axis of symmetry; so the two zeros are -6 and +3.

I'm guessing that is what the first question was supposed to be asking:
a. The two roots are -6 and 3.

Since the two roots are -6 and 3, the equation is
y+=+%28x%2B6%29%28x-3%29+=+x%5E2%2B3x-18
so

b. q=3; r = -18