Square root property

Revision as of 23:55, 15 May 2014 by Hwl0304 (talk | contribs) (Second format)

The square root property is a method for solving quadratic equations.

Method

First we must convert the quadratic to either the form $ax^2=b$ or $(yx+z)^2=w$.

First format

$x^2=18$

take the square root of both sides

$x=\pm\sqrt{18}$

so the roots are $\sqrt{18}$ and $-\sqrt{18}$.

Second format

$(3x+4)^2=5$

take the square root of both sides

$3x+4=\pm\sqrt{5}$

isolate $x$

$x=\frac{\pm\sqrt{5}-4}{3}$