SOLUTION: Here is the problem: Determine without graphing, whether the given quadratic function has a minimum value or maximum value. Then find the x and y coordinates of the minimum or the

Algebra ->  Algebra  -> Rational-functions -> SOLUTION: Here is the problem: Determine without graphing, whether the given quadratic function has a minimum value or maximum value. Then find the x and y coordinates of the minimum or the      Log On

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 Algebra: Rational Functions, analyzing and graphing Solvers Lessons Answers archive Quiz In Depth

 Click here to see ALL problems on Rational-functions Question 88807: Here is the problem: Determine without graphing, whether the given quadratic function has a minimum value or maximum value. Then find the x and y coordinates of the minimum or the max point f(x)=X^2-2x-8 Here is what I have done x=- b/2a x=- -2/2(1) x=2/2(1) x=2/x x=1 f(1)=(1)^2-2(1)-8 f(1)=(1)-2(1)-8 f(1)=(1)-2-8 f(1)=-1-9 f(1)=-9 Is this right? Answer by bucky(2189)   (Show Source): You can put this solution on YOUR website!Given: . f(x)=X^2-2x-8 Here is what I have done x=- b/2a <=== ok x=- -2/2(1) <=== ok x=2/2(1) <=== ok x=2/x <=== should be 2/2 x=1 <=== ok f(1)=(1)^2-2(1)-8 <=== ok f(1)=(1)-2(1)-8 <=== ok f(1)=(1)-2-8 <=== ok f(1)=-1-9 <=== you probably meant -1 - 8 f(1)=-9 <=== ok . You used a good process. And the point you found (1,-9) is the correct point. But you didn't mention whether is was a maximum or a minimum point. It is a minimum point and you can tell that because the x^2 term is preceded by a + sign. If the x^2 term had been -x^2 then the point you found would have been a maximum point on the curve. . You have the correct idea on how to do the problem. . Another thing you can tell about this graph from the work you have done is that the graph crosses the x-axis at two points. You can tell this because the minimum point occurs where y = -9. The graph is a parabola that rises from that point. Therefore, in rising the parabola must cross the x-axis in two locations ... one to the left of x = +1 and one to the right of x = +1 on the x-axis. Hope this makes sense. Anyhow, good work!!! .