# Quadradic

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• July 15th 2007, 11:21 AM
getnaphd
Quadradic
x^2-7x=3

and

x+8=1-x^2

Dont even know where to begin

Please help..
• July 15th 2007, 01:08 PM
CaptainBlack
Quote:

Originally Posted by getnaphd
x^2-7x=3

and

x+8=1-x^2

Dont even know where to begin

Please help..

These are quadratics, rearrange then into standard form then apply the
quadratic formula.

The first can be rearranges to $x^2-7x-3=0$. Now the quadratic
formula tells us that if we have a quadratic $ax^2+bx+c=0$, then:

$
x=\frac{-b \pm \sqrt{b^2-4ac}}{2a}
$

In the current case $a=1,\ b=-7,\ c=-3$, so:

$
x=\frac{7 \pm \sqrt{49+12}}{2}
$

RonL