Question 955262
The answer MUST be negative. If it is positive,the first term on the left is at least 3 and 3/4 (15/4) with only another positive term to add.No way to add positive to get a smaller number (2/3). Check your answer in the original equation (you can use decimals) and you may find you were right all along. 
{{{(x+15)/4+3x/5=2/3}}}
{{{(15/15)((x+15)/4)+(12/12)(3x/5)=(2/3)(20/20)}}}
{{{(15x+225)/60+36x/60=40/60}}}
{{{15x+225+36x=40}}}
{{{51x+225=40}}}
51x=-185
x=-185/51