Answer:
you can watch YT videos or search online. search: How to solve proofs. Also search up proof theorems. This will help you even more towards solving more complex proof problems.
Step-by-step explanation: 
 
        
             
        
        
        
Hi! took the quiz, it's associative properties
 
        
                    
             
        
        
        
Hiya. I'm going to rewrite the second equation.
By subtracting 5x by both sides, I'll be able to have y by itself:
-y=-5x+13
I'm going to then divide both sides by -1 to get:
y=5x-13.
Then, I'm going to plug that equation into the first equation 
3x+2(5x-13)=39
Factor:
3x+10x-26=39
Combine like terms:
13x=65
Divide both sides by 13 to get x by itself to get x=5
Plug this back into the equation of y=5x-13
y=5(5)-13 to get y=12
 
        
                    
             
        
        
        
Answer:
ewan ko sayo tanong ka sa mama mo