How do you solve #|x + 6| = 2x# and find any extraneous solutions?

1 Answer
Jun 16, 2016

Answer:

#x=-2# if #x<-6#
#x=6# if#x>=-6#

Explanation:

Knowing the property of absolute value that says:

if#|x|=a# then
#x=-a , x<0#

#x=a,x>=0#

Applying the above property we have:

#x+6=-2x,x+6<0#. Eq(1)

#x+6=2x,x+6>=0#. Eq(2)

Solving the above equations we have:

Eq(1): if #x+6<0# that is #x<-6#
#x+2x=-6#
#3x=-6#
#x=-6/3=-2#
So,
#x=-2,x<-6#

Eq(2): if #x+6>=0# that is #x>=-6#

#x+6=2x#
#x-2x=-6#
#-x=-6#
#x=6# whenever #x>=-6#