Question 83513
{{{x-a=-x+a+4b}}} Start with the given equation


{{{x=-x+a+a+4b}}} Add "a" to both sides


{{{x+x=2a+4b}}} Add x to both sides


{{{2x=2a+4b}}}


{{{x=(2a+4b)/2}}} Divide both sides by 2


So this is our answer


{{{x=a+2b}}}