How do you solve #3x ( x - 2) = 6x - 8#?

1 Answer
Feb 19, 2017

#x = 3.155 " or " x =0.845#

Explanation:

Multiply out first.

#3x(x-2) = 6x-8#

#3x^2 -6x=6x-8" "larr# make the quadratic = 0.

#3x^2 -6x-6x +8 =0#

#3x^2 -12x+8=0" "larr# this does not factorise

We can use completing the square or the quadratic formula.

#x^2 -4x +8/3 =0" "larr div 3#

#x^2 -4x color(blue)(+4-4)+8/3 =0" " larrcolor(blue)((b/2)^2)#

#(x-2)^2 -4/3 =0#

#x-2 = +-sqrt(4/3)#

#x = +sqrt(4/3)+2 = 3.155#

#x = sqrt(4/3)+2 = 0.845#