+0  
 
+1
346
2
avatar+1405 

Help me, please

solve by addition or subtraction

 

y=2x+3

+ x+3y=-5

 Sep 25, 2017
 #1
avatar+96104 
+2

y = 2x +3        subtract 2x from both sides ⇒  -2x + y =  3

1x+3y= -5

 

The idea is to focus on eliminating a variable......I see that by multiplying the second equation by 2 we can add it to the first equation and eliminate x

 

So........we have

 

-2x + y =  3

2x + 6y = -10

___________

        7y  = - 7        divide both sides by 7

          y = -1

 

Sub this into  any equation to find x

 

y = 2x + 3

-1 = 2x + 3     subtract 3 from both sides

-4 = 2x        divide both sides by 2

x = -2

 

 

 

cool cool cool

 Sep 25, 2017
 #2
avatar+18 
+2

you are solving by additon wink

 Sep 25, 2017

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