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

1 Answer
Sep 18, 2015

Answer:

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

Explanation:

#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.)