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How do u solve x-y=2 and x+y=1?

+1 vote
Its has to do with linear equations
asked Mar 2, 2013 in ALGEBRA 1 by mathgirl Apprentice

3 Answers

+1 vote

x-y = 2
x = 2+y

substitute to next equation

x+y = 1
(2+y) + y = 1
2+2y=1
2y = 1-2
2y= -1
y = -(1/2)

substitue again

x-y = 2
x- (-1/2) = 2
x+1/2 = 2
x = 2- (1/2)
x = 3/2

answer: (3/2 , -1/2)

answered Mar 2, 2013 by kevin Rookie
0 votes

x-y=2
x+y=1
------------
2x = 3
divide each side by 2
x =3/2
substitute x =3/2 in x+y=1
3/2 + y = 1
subtract 3/2 form each side
y = 1- 3/2 = -1/2
(x, y) = (3/2, -1/2)

x=1.5

answered Mar 2, 2013 by John Lyn Pupil
0 votes

x-y = 2
y=x-2

substitute to next equation

x+y = 1
x+x-2 = 1
2x-2=1
2x = 1+2
2x= 3
x = 3/2

substitue again

3/2-y = 2
y=(3/2)-2
y = -1/2

answer: (3/2 , -1/2)

solution to the system of equation x-y=2 and x+y=1 is ( 3/2 , -1/2 )

answered Mar 3, 2013 by casacop Expert
edited Mar 3, 2013 by casacop

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