Answer:
After 23 years , the capital will get three times as big
Step-by-step explanation:
Firstly, let us write the compound interest formula 
P = I( 1 + r)^n
Since we are considering a capital rise of 3 times 
If I, the initial value is x, the P
value later will be 3x
Interest rate is 5/100 = 0.05
so we need the value of t
This will be;
3x = x(1 + 0.05)^t
3= 1.05^t
ln 3 = t ln 1.05
t = ln 3/ln 1.05
t = 23 years 
 
        
             
        
        
        
10*8=80
3*8=24
80-24=56
You would save $56.00 in 8 weeks
        
                    
             
        
        
        
I like the substitution method. Which is when you make one equation equal only x or y and plug it into the other equation)
There is also the graphing method. If you graphed it, it might not be quite as accurate (at least on hand, on computer you would be pretty exact)
Then there is the elimination method. You multiply one of the equations by a coefficient so that you can eliminate x or y from the equation. 
        
             
        
        
        
Answer:
B
Step-by-step explanation:
6x5=30
30x2/3=20
 
        
             
        
        
        
Answer:
8z+12
Step-by-step explanation: