You can not "solve" this, so to speak, rather simplify this expression. Take the "2" and multiply that by the "a" and the "3" in the parentheses. You will then have the simplified answer of: 2a times 6.
Hope that helps!
Answer:
Sports players: For people that need high respiratory performance, rises in the pressure may difficult the things, so they would be affected by high pressure because this makes breathing a little bit harder.
Workers in construction and such: People that work a lot with their muscles, in heat environments (road workers, construction workers) may be affected by the same problem as before, and this makes the workers to exhaust in a shorter time than if they worked in a lower pressure environment.
Scientist: A lot of time, some experiments or investigations need a specific pressure to work, so changes in weather pressure may affect investigations, and because the changes are actually uncontrollable, the scientist are really affected by them.
10 because x+x = 20
a+b=c