How do you solve the following linear system: -x + y = 3, x + y = 5 ?

1 Answer
EZ as pi
Apr 16, 2018

x=1 and y=4

Explanation:

Note that the two x-terms are additive inverses, so if you add the two equations, the x-terms will be eliminated:

" "color(blue)(-x)+y = 3" "....... A
" "color(blue)(+x)+y = 5" "......."B

A+B:" "2y =8
color(white)(xxxxx.xxx) y=4

Substitute y=4 into equation B to get x=1

Checking in both equations gives:

-1+4=3
+1+4=5

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