"Product" means multiply so you would want to multiply g and h together. You put it in parenthesis because you want to multiply the solution you get from multiplying g and h by 10. To show this, you can simply just put the 10 in front of the parenthesis as that implies multiplication.
C - In any triangle two sides taken together in any manner are greater than the remaining one. So 10+7=17, the greatest length of the 3rd side is 16. 16+17=33
