How do you simplify $x sqrt 18 - 3 sqrt(8x^2)$ ?

Question

1740 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2015-09-18T22:34:20

$xsqrt(18) - 3sqrt(8x^2) = -3xsqrt(2)$

$xsqrt(18) - 3sqrt(8x^2) =$
$xsqrt(9*2) - 3sqrt(4*2*x^2)=$
$3xsqrt(2)-6xsqrt(2)=$
$-3xsqrt(2)$

(That is, if and only if, $x >=0$ , if not $3xsqrt(2)-6|x|sqrt(2)$ , because everything that comes out of a root must be positive or a zero.)

How do you simplify x *sqrt 18 - 3 * sqrt(8x^2)x *sqrt 18 - 3 * sqrt(8x^2)?