345= 3 hundreds, 4 tens, and 5 ones 
391= 3 hundreds, 9 tens, and 1 one
You can use the model I attached to help u see it better.
Hope this helps!
 
        
        
        
This is a cubic equation  so it will have a total of three roots.
there is only one change of sign  so the equation will have one positive real  root.
The other 2 roots  will be negative  and might be real or complex
        
             
        
        
        
Scale Factor=4
I just counted how many units GF was and I came out with 5. Then I looked at the length of G’F’ and saw that it was at 20 units. 20/5=4
        
             
        
        
        
6 x 2 minus 20 because 6 x 2 is in parenthesis so it comes first