Ok so first I am assuming you ment 2 sevenths so 12 divided by 2 sevenths is 42. so the father is currently 42. so when she was 10 he was 40. since 10 is 4 times 40 that is the age we need. so 42 minus 40 is 2. therefore the answer is 2.
        
             
        
        
        
Answer:
4
Step-by-step explanation:
calculate the sum 4*1 any expression is multiplied by 1 remains the same solution is 4
 
        
             
        
        
        
Answer:
-a(a+4)/(16 - a²)
Step-by-step explanation:
             a/(a - 4)                  Multiply by (a + 4)/(a + 4)
= a(a + 4)/[(a – 4)(a + 4)]     Multiply the denominatorator terms
= a(a + 4)/(a² - 16)               Multiply by -1/(-1)
= -a(a+4)/(-a² + 16)              Reorder terms in denominator
= -a(a+4)/(16 - a²)
 
        
             
        
        
        
Okay so this is how I got the answer.... I didn’t lol