SOLUTION: Happy Tuesday everyone! I am looking for some expertise when it comes to solving "story" or "word" problems dealing with quadratic equations. My teacher requires that when we work
Question 362033: Happy Tuesday everyone! I am looking for some expertise when it comes to solving "story" or "word" problems dealing with quadratic equations. My teacher requires that when we work through a problem that we show her all of the steps to show what we did to get our answer. I was wondering if you could help me?
11.5, #10
Directions: Solve
10.) The daily number of request, f(x), for a song that a local radio station receives can be modeled by f(x)=x^2-5x+11 (it should read x squared)
where x is the number of days after the song has been released. During which time period will the daily number of requests be below 7?
The book shows the answer to be: between day 1 and 4. But, I have not a clue what steps I need to perform to get this as my final outcome. Thanks so much! Found 2 solutions by ewatrrr, solver91311:Answer by ewatrrr(24785) (Show Source):
Hi,
requests to be played after release time x model:
f(x)=x^2-5x+11
7 = x^2 - 5x + 11
-4 = x^2 - 5x
x = 1 or x = 4 graph indicates that as well
graph will be below the '7 line' when x is between 1 and 4
The graph of your function is a parabola opening upward. What you want are the x-coordinates of the two intersecting points between your parabola and the horizontal line . All you need to do is set your function equal to 7 and then solve the resulting quadratic equation.
Solve for . Hint: It factors.
John
My calculator said it, I believe it, that settles it
