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 Occasionally, if you want to use equation combination to get rid of a variable, you’ll have to multiply each equation by a different number.
  
 
For example, in the following question, a good strategy for getting rid of y is to multiply 
      the first equation by –5 and the second equation by what number?  
        
             
           
       
      
   
    In the space provided, type the number you would multiply the second
    equation by to make y cancel out, then click Continue.  
         
Answer: 2 
  
If you choose –5 for the first equation, you’ll want to select 2 for the second equation to make the y-variable disappear:  
       
            
           
       
Added together, y will drop out, and you’ll be able to solve for x. 
Now let’s move on to our second method…substitution. 
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