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-2.5x+y=13.5

2.25x-y=-12.25

 Oct 14, 2015
 #1
avatar+106515 
+5

-2.5x+y=13.5

2.25x-y=-12.25

 

Using the first equation,  y = 13.5 + 2.5x....so ....putting this into the second equation, we have......

 

2.25x - [ 13.5 + 2.5x]  = -12.25       simplify

 

2.25x - 13.5 - 2.5x  = -12.25            let's multiply by 100 to clear the decimals

 

225x - 1350 - 250x = - 1225      add 1350 to both sides, simplify the left side

 

-25x = 125   divide both sides by -25

 

x = --5

 

And using

 

y = 13.5 + 2.5x   →  y = 13.5 + 2.5(-5)   →  y = 13.5 - 12.5   = 1

 

 

 

cool cool cool

 Oct 14, 2015

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