elimination x+y=9 2x-y=-3?

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elimination x+y=9 2x-y=-3?

2007-02-11 08:08:49 · 3 answers · asked by Sujashni J 1 in Science & Mathematics ➔ Other - Science

3 answers

x+y=9
2x-y=-3
------------
3x=6
x=2

2+y=9
-2 -2

y=7
x=2
Hope this helps!!

2007-02-11 08:16:19 · answer #1 · answered by Anonymous · 0⤊ 0⤋

Multiply first equation by 2 and subtract the second equation from that.

2x + 2y = 18
-2x + y = 3

3 y = 21

Thus y = 7

Substitute in equation No.1:

x + 7 = 9
x = 2

Check with the second equation:

2 X 2 - 7 = - 3

So our answer is correct.

2007-02-11 08:31:08 · answer #2 · answered by Swamy 7 · 0⤊ 0⤋

2x-y=-3
2x+3=y
x+2x+3=9
3x=6
x=2
y=7

2007-02-11 08:13:10 · answer #3 · answered by xandrasings 2 · 0⤊ 0⤋