Answer:
14.
Step-by-step explanation:
1) if the sides of the given triangle are 'a'=9, 'b'=x and 'c'=x+2, then its perimeter can be written as: P=a+b+c or P=9+x+x+2;
2) if according to the condition P=35, then 9+x+x+2=35;
2x=24; ⇒ x=12;
3) if x=12, then a=9; b=12 and 14;
4) finally, c=14 - the required longest side.