SOLUTION: solve the linear system using the substitution method y=2x+1 and y=-2x

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Question 1103441: solve the linear system using the substitution method
y=2x+1 and y=-2x
Found 2 solutions by josgarithmetic, ikleyn:
Answer by josgarithmetic(39623) About Me  (Show Source):
You can put this solution on YOUR website!
2x%2B1=-2x
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You need to work all the way through and SOLVE that first equation, which IS the first substitution step.

graph%28300%2C300%2C-3%2C3%2C-3%2C3%2C2x%2B1%2C-2x%29

Answer by ikleyn(52835) About Me  (Show Source):
You can put this solution on YOUR website!
.
In the first equation replace "y" in the left side by "-2x" based on the second equation.


It is how the Substitution method works in this case.


Then you get the single equation for the only unknown "x":


-2x = 2x + 1,   which implies


-2x - 2x = 1  ====>  -4x = 1  ====>  x = -1%2F4.


Then from the second equation you get "y":


y = -2x = %28-2%29%2A%28-1%2F4%29 = 1%2F2.


Answer.  The solution is  x= -1%2F4,  y= 1%2F2.

Solved.