3x + 9 + 3x =15
6x + 9 = 15
 - 9 = -9
6x = 6
/6 /6
X =1
        
             
        
        
        
The sum of 31/4+42/4= 18.25
<u>Step-by-step explanation</u>:
- The denominators are same. 
 - Then add the numerators and keep the denominators same.
 
The sum of (31/4) + (42/4) = (31+42)/4 
⇒ 73/4
⇒ 18.25 
 
        
             
        
        
        
there is no picture. Can you upload a picture?
 
        
             
        
        
        
Answer:
x=9
Step-by-step explanation:
We can use similar triangles and ratios.  Put the small triangle side over the large triangle side.
9cm            3x -20
----------   = ----------------    We need to add the sides to get to the larger triangle
72+9 cm   3x-20 + 56
We can cross multiply to solve
9 * (3x-20+56) = (72+9) * (3x-20)
Simplify
9*(3x+36) = 81*(3x-20)
Distribute
27x +324 = 243x -1620
Subtract 27x from each side
27x-27x +324 = 243x-27x -1620
324 = 216x-1620
Add 1620 to each side
324+1620 = 216x
1944 = 216x
Divide each side by 216
1944/216 = 216x/216
9=x
 
        
                    
             
        
        
        
Answer:
15.98
Step-by-step explanation:
∑₁¹⁰ 
We have to use the formula of sum of a G.P. series with common ratio r < 1.
If the first term is a, the common ratio is r and the number of terms is n then the sum [a + ar + ar² + ar³ + ......... up to n terms] is given by  
 (Answer)