How do you solve $x^2=9$ using the quadratic formula?

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Answer 1 · 2016-02-27T15:21:55

$x=+-3$

Write as : $" "x^2-9=0$

Compare to standard form of: $" "ax^2+bx+c=0$

Where: $" " x=(-b+-sqrt(b^2-4ac))/(2a)$

$a=1$
$b=0$
$c=-9$

So by substitution you have:

$x=(-0+-sqrt(0^2-4(1)(-9)))/(2xx1)$

$x=+-sqrt(+36)/2$

$x=+-sqrt(6^2)/2$

$x=+-3$

Tony B

How do you solve x^2=9x^2=9 using the quadratic formula?