+0  
 
+1
165
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avatar+1117 

Use the addition method to solve this.

 

 6x + 5y = 2

 

-2x + 7y = 34

 Apr 30, 2019
edited by SmartMathMan  Apr 30, 2019
 #1
avatar+106535 
+2

 

Multiply the bottom  equation through by 3

This gives the system

 

6x +  5y  = 2

-6x + 21y = 102       add these

 

26y  =  104       divide both sides by 26

y = 4

 

And

 

6x + 5(4)  = 2

6x + 20 = 2        subtract 20 from both sides

6x  = -18     divide both sides by 6

x = -3

 

So   { x, y}  =  { -3, 4 }

 

 

cool cool cool

 Apr 30, 2019
 #2
avatar+1117 
+2

I tried it a completely different way, maybe that's why I got it wrong.

SmartMathMan  Apr 30, 2019
 #3
avatar+106535 
0

There is no "set" way to do these, SMM......the idea is to multiply one equation by something so that when we add the result to the other equation, a variable will "drop out".....

 

 

cool cool cool

CPhill  Apr 30, 2019

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