View Full Version : Finding roots of a quadratic equation
Canucks16
Jan 3, 2009, 12:38 PM
I need to know how to find the roots of a quadratic. For example 5x^-4x=9x+6
a walkthrough of the qestion would be fantastic
v1033
Jan 3, 2009, 04:03 PM
5x^-4x=9x+6
well the first thing to do is get everything onto one side so the quadratic =0
5x^-13x-6=0
then we need to factorise the equation so we think about the coeffiecents
5 is prime so we start our brackets
(5x ? )(x ? )=0
6 = 2x3 or 1x6 and we need -6 so we will have a - somewhere
15 = 3x5 - 2x1 so
5x^-13x-6=(5x+2)(x-3)
(5x+2)(x-3)=0 so 5x+2=0 or x-3=0
so x=3 or x=-2/5
let me know if you need further clarification
Canucks16
Jan 3, 2009, 04:44 PM
That's great thanks
EuRa
Jan 4, 2009, 09:09 AM
Yeah that or the Quadratic formula.
-B ± √ ( B² - 4AC)
_________________
2A
Where A B and C = Ax² + Bx + C