Solve the following quadratic equation using formula method only … - Vidyadip

Question

Solve the following quadratic equation using formula method only
$x^2-4 \sqrt{15} x-4=0$

✓

Answer

$x ^2-4 \sqrt{15} x -4=0$
$a =1 ; b =-4 \sqrt{15} ; c=-4 $
$ D = b ^2-4 ac $
$ =(-4 \sqrt{15})^2-4(1)(-4)$
$ =240+16 $
$=256 $
$ x =\frac{- b \pm \sqrt{ b ^2-4 ac }}{2 a} $
$ x =\frac{4 \sqrt{15} \pm \sqrt{256}}{2} $
$ x =\frac{4 \sqrt{15}+16}{2}, x =\frac{4 \sqrt{15}-16}{2} $
$x =2 \sqrt{15}+8, x=2 \sqrt{15}-8$

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