I am assuming you mean:
\(\displaystyle \frac{x+5}{2}+\frac{x+2}{7}=2\)
What Stapel is tryng to say is to use proper grouping symbols. The way you have it can be construed in various ways.
You could write it as (x+5)/2+(x+2)/7=2. That way we know what you mean. The way you have it you could mean
\(\displaystyle x+\frac{5}{2}+x+\frac{2}{7}=2\). Unless that is what you mean.
Anyway, assuming the former, multiply through by the LCD, which is 14. That will eliminate the fraction and you can proceed.
Okey-doke?.