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  • 26-03-2017
  • Mathematics
contestada

-7x + 8y = 19
5x + y = 20

Respuesta :

almaren
almaren almaren
  • 26-03-2017
x = 3
y = 5
(3,5)
I used substitution because It seemed the easiest.
From the second equation I isolated it for Y to get y=20-5x

I plugged this in to the other equation for the Y value to perform substitution.

-7x + 8 (20-5x) = 19
then it's simple algebra

-7× + 160 - 40x = 19
-47x + 160 = 19

subtract 160 from both side and divide both side by -47 to isolate x.

-47x = -141
x=3

then to find Y, simple plug this into one of the equation above. or simply use this one that we already isolated for Y:
y=20-5x
y=20-5 (3)
y=5

hope that helps
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