2007-10-15 09:51:47 · 4 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
2x + y = 8
x - y = 10
________
3x = 18
x = 6
y =-4
2x + 3y = -14
2x + 2y = 4 (multiply x -1)
2x + 3y = -14
-2x - 2y = -4
_____________
y = -18
Hence 'x' is
2x + 2(-18) = -14
2x - 36 = -14
2x = -14 + 36
2x = 22
x = 11
2007-10-15 09:58:39 · answer #1 · answered by lenpol7 7 · 0⤊ 0⤋
well you don't have to use all the equations.
Let's take: 2x + 2y = 4
---divide by 2---
you get: x + y = 2
---solve for x---
x = 2-y
Take: x - y = 10
---solve for x--
x= 10 + y
so now you have:
1) x = 2 - y
2) x = 10 + y
subtract 2) by 1), you get: 0 = 8 + 2y
solve for y, you get y=-4
put it back into either 1) or 2) and you solve for x. X=6.
plug it into the other given equations and check to make sure that answer is correct.
2007-10-15 17:02:51 · answer #2 · answered by ryuryubu 2 · 0⤊ 0⤋
Multiply x-y=10 by 2. Then multiply 2x+y=8 by -1. All the x's should cancel when you add all of the equations
2007-10-15 16:56:24 · answer #3 · answered by R 2 · 0⤊ 0⤋
Holy crap..i have the same problems..haha..im doin my homework..ha..thats crazy..if u find out tell me..i have no idea how to..sorry
2007-10-15 16:56:04 · answer #4 · answered by none 1 · 0⤊ 0⤋