x= -1 and y=2
1) Let's solve that Linear System of Equations
x+y=1
-2x+y=4
We can apply the Elimination Method, so let's multiply the first equation by 2, and then cancel out the x term, this way:
x+y=1 x2
-2x+y=4
2x+2y=2
-2x+y=4
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3y = 6 Divide both sides by 3
y= 2
2) Now we can plug into the first equation (the simplest one) y=2 and solve it for x.
x+y=1
x + 2 = 1
x +2 -2 = 1-2 Subtract 2 from both sides
x= -1
3) Hence the one who is correct found x= -1 and y=2