• Sep 21st 2010, 06:21 PM
ineedhelp1111

please someone explain this to me and be as descriptive as possible i would really appreciate.

4x^2-12x+9=0

i know i have to plug them in into the quadratic formula but every time i solve this i always get a different answer and i dont get why please someone explain this to me or do it to me so i know what im doing wrong
• Sep 21st 2010, 07:31 PM
Wilmer
4x^2 - 12x + 9 = 0
(2x - 3)(2x - 3) = 0
• Sep 21st 2010, 08:00 PM
Educated

$\dfrac{-b\pm\sqrt{b^2-4ac}}{2a}$

Now when you substitute values into the quadratic formula, the discriminant ( $\sqrt{b^2-4ac}$) determines the amount of 'roots' or answers there are because of the plus/minus before it.

If the discriminant is above 0, there are 2 answers.
If the discriminant is equal to 0, there is 1 answer.
If the discriminant is below 0, there are 0 answers.

$ax^2 + bx + c = 0$