the original equation was 2x+7y=13
2x+3y=5
2007-02-22 09:31:18 · 8 answers · asked by andrew 3 in Science & Mathematics ➔ Mathematics
2x+7y=13
2x+3y= 5
subtract the equations to elimiate one variable
4y = 8
y = 2
since 2x+3y = 5
2x+ 6 = 5
2x = -1
x = -1/2
2007-02-22 09:36:26 · answer #1 · answered by Brian F 4 · 0⤊ 0⤋
(2x+7y=13) + (2x+3y=5) = 4x+10y=18
4x+10y=18 / 2= (2x + 5y=9)
y=1 x=2 therefore (4 + 5= 9)
2007-02-22 17:43:05 · answer #2 · answered by whatevit 5 · 0⤊ 0⤋
ok, first you must reconfigure your problem...
change 2x + 3y =5 to -2x -3y = -5 it's the same thing....
now add that to your other equation, this gives you
4y = 8 therefore y = 2
plug y back into any of your equations...
and you'll see that x = - (1/2) and y = 2
2007-02-22 17:37:14 · answer #3 · answered by Mojo 2 · 0⤊ 0⤋
Here, it is better to use the subtraction half of the elimination method
so,
2x + 7y = 13
-2x - 3y = -5
-----------------
0x + 4y = 8
y = 2
2x + 6 = 5
x = -1/2.
2007-02-22 17:37:12 · answer #4 · answered by Paranoid Android 4 · 0⤊ 0⤋
When you come down to this, you say to yourself, "4x what +10x what=18. So 4x2=8 and 10x1=10, so therefore 10+8=18 and therefore x=2 and y=1
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2007-02-22 17:37:32 · answer #5 · answered by swimmerdude 2 · 0⤊ 0⤋
are you eliminating x? if so 4x+10y=18
subtract 10y from both sides of the equation leaving 4x=18-10y then divide both sides of the equation by 4 leaving x=18-10y / 4
2007-02-22 17:43:14 · answer #6 · answered by christy r 1 · 0⤊ 0⤋
2x+7y=13
- 2x+3y=5
4y=8
y=2
2x=5-(3*2)
2x=5-6
x=-1/2
2007-02-22 17:42:33 · answer #7 · answered by mitch v 1 · 0⤊ 0⤋
you can divide by 2 or 4 and get 2x=5y+9 or x=2.5y+4.5
2007-02-22 17:38:10 · answer #8 · answered by jim m 5 · 0⤊ 0⤋