Answer:
21 + 3a
Step-by-step explanation:
3 (7+a)
distribute 3 into parentheses:
21 + 3a
 
        
                    
             
        
        
        
11/21 would be the answer
        
             
        
        
        
Hello.
In 10 years, his age will be

The sum of his current age and 10 equals his age in 10 years.
2 years ago his age was

The difference of his current age and 2 equals his age 2 years ago.
7 years ago his age was

The difference of his current age and 7 equals his age 7 years ago.
Therefore, his age after 10 years will be  , his age 2 years ago was
, his age 2 years ago was  , and his age 7 years ago was
, and his age 7 years ago was 
I hope it helps.
Have a nice day.

 
        
                    
             
        
        
        
Step 1. 100-15=85
Step 2. $350 *.85=$297.50
Step 3. $297.50 * .06= $17.85
Step 4. $297.50+17.85=$315.35
Answer: $315.35