Question 1069065
I am assuming that you want to find the solution to this equation. 

Combine the like terms (x and -2x), which would result in -x. 

Now you have {{{-x + 15 = 0}}}. 
Subtract 15 from both sides. 
{{{-x = -15}}}
Divide both sides by -1. 
{{{x = 15}}}