How do you solve $(x + 4)^2 = 81$ using the square root property?

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Answer 1 · 2015-08-13T15:30:22

The solutions are
$color(blue)(x=5, x=-13$

The square root property involves taking the square root of both the terms on either side of the equation.

Applying the same to the given equation:

$sqrt((x+4)^2)=sqrt(81$

( $sqrt81= color(blue)(+-9$ )

So,
$sqrt((x+4)^2)=color(blue)(+-9$

$(x+4)=color(blue)(+-9$

Solution 1:
$x+4 = +9$
Isolating $x$
$x+4 -color(blue)(4)= +9-color(blue)(4)$
$color(blue)(x=5$

Solution 2:
$x+4 = -9$
Isolating $x$
$x+4 -color(blue)(4)= -9-color(blue)(4)$
$color(blue)(x=-13$

How do you solve (x + 4)^2 = 81(x + 4)^2 = 81 using the square root property?