use the square root property

**lovely08** · December 11th 2007, 01:07 PM

(x+20)squared = 49

**wingless** · December 11th 2007, 01:14 PM

$(x+20)^2 = 49$
We can square root both sides.

If $x^2 = a$ , then $|x| = \sqrt {a}$ .
NOT $x = \sqrt {a}$ !!

So,
$(x+20)^2 = 49$
$|x+20| = \sqrt{49}$
$|x+20| = 7$
$x+20 = +7$ and $x+20 = -7$

$x+20 = +7$
$x = -13$

$x+20 = -7$
$x = -27$

$x = \{-27,-13\}$

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