Question 102086
I think this is your equation and you want to solve for x. 
{{{3(x+6) = 3(x-6)}}}
{{{3x+18 = 3x-18}}} Use the distributive property
Next step, variables (unknowns) on one side, knowns on the other.
{{{3x+cross(18)-cross(18) = 3x-18-18}}} Use the additive inverse of 18 or (-18).
{{{3x = 3x-36}}}  Simplify.
{{{3x - 3x = 3x - 3x -36}}} Use the additive inverse of 3x or (-3x).
{{{0 = -36}}} 
Huh? Your equation leads to an inconsistency since 0 obviously does not equal (-36). There is no solution for x. In other words, there is no value for x where this equation works.