+0

0
98
2
+272

So I got these problems and we didn't go over this in class.

What value of x will give the minimum value for 9x^2 + 18x + 7?

WhichWitchIsWhich  Oct 23, 2017

#1
+5927
+1

The x value that gives the minimum or maximum value for a quadratic function,

ax2 + bx + c  ,  is         - $$\frac{b}{2a}$$    .

So for this one...

The x value that gives the minimum or maximum value for

9x2 + 18x + 7   is       - $$\frac{18}{2(9)}$$  =  - 1   .

And in this case,  9  is positive, so the parabola opens upward, and we have a minimum.

hectictar  Oct 23, 2017
edited by hectictar  Oct 23, 2017
Sort:

#1
+5927
+1

The x value that gives the minimum or maximum value for a quadratic function,

ax2 + bx + c  ,  is         - $$\frac{b}{2a}$$    .

So for this one...

The x value that gives the minimum or maximum value for

9x2 + 18x + 7   is       - $$\frac{18}{2(9)}$$  =  - 1   .

And in this case,  9  is positive, so the parabola opens upward, and we have a minimum.

hectictar  Oct 23, 2017
edited by hectictar  Oct 23, 2017
#2
+272
+1

:D  👍

WhichWitchIsWhich  Oct 23, 2017

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