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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)
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2A


Where A B and C = Ax² + Bx + C