Posted by **barb** on Friday, November 12, 2010 at 11:57pm.

I only have 1 hour to get this question answered. Thank you in advance. I need a quadratic equation in the variable x given the solutions:

-7 sqrt 7, and 7 sqrt 7

This needs to be in the standard form of ax^2+bx+c=0.

Can someone please help me with this???? I am so lost!!!!

- PLEASE HELP ME MATH -
**MathMate**, Saturday, November 13, 2010 at 12:48am
For a quadratic equation with given zeroes z1 and z2, the equation is:

(x-z1)(x-z2)=0

In the given case, z1=-7√7 and z2=7√7.

Expand and simplify the resulting expression on the left-hand-side, and equate coefficients of powers x², x and constant term to get the values of a, b and c.

I gave you response to a similar question, except that I forgot the variable x, which should have read:

x² -5√5**x** -30 = 0

see:

http://www.jiskha.com/display.cgi?id=1289541351

- PLEASE HELP ME MATH -
**barb**, Saturday, November 13, 2010 at 1:00am
I understand, although mathlab checked it wrong and gave me this problem. I SIMPOLY do not understand this when it comes to radicals. And furthermore mathlab has a habit of checking problems wrong when they are indeed right.I understand how to FOIL, I just do not know how to work the radicals, CAN YOU PLEASE HELP ME!!!! This is due in 1 hour. Thank you so much!!!

- PLEASE HELP ME MATH -
**bobpursley**, Saturday, November 13, 2010 at 7:10am
And you are paying for Mathlab?

- PLEASE HELP ME MATH -
**Reiny**, Saturday, November 13, 2010 at 8:15am
Just follow MathMate instructions and set it as

(x - 7√7)(x+7√7) = 0

looks like the difference of squares pattern, so ...

x^2 - 343 = 0

then

a=1

b=0

c=-343

try that as input

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