x-y=7
2x+y=2
2006-09-14 09:26:49 · 8 answers · asked by Exclusive [♥] 6 in Science & Mathematics ➔ Mathematics
multiply first equation by -2
-2x+2y=-14
2x+ y= 2
----------------------------- add
0 x + 3y = -14+2
3y = -12
y = -4
in first equation replace y
x-(-4) =7
x+4=7
x=3
=> x=3; y=-4
2006-09-14 09:32:11 · answer #1 · answered by Anonymous · 4⤊ 0⤋
2 simple simultaneous equations
an equivalent equation to the first is -2x +2y = -14 (mult by -2)
Then add the derived equation above to the second given..... giving....
0 x + 3 y = -12.
y = -4....... right?
then plug in the solved value for y in any of the original equations.
2006-09-14 09:38:33 · answer #2 · answered by rhino9joe 5 · 1⤊ 1⤋
First, solve the first equation for x:
x = 7 + y
Then plug that x-value into the second equation:
2*(7+y) + y = 2
Get rid of the parentheses:
14 + 3y = 2
Solve that for y, and you get y=-4
Plug that y-value into the first equation, and you get x=3.
Hopefully that helps!
2006-09-14 09:35:12 · answer #3 · answered by Bramblyspam 7 · 2⤊ 1⤋
solve the first equation for x, and you get x = 7+y
Now substitute this into the next equation for x, and you get
2*(7+y)+y = 2.
Now solve this for y, and you get y =-4. Now plug this into the equation you solved for x, and you get x = 7-4=3.
So x = 3 and y = -4
2006-09-14 09:33:37 · answer #4 · answered by 1,1,2,3,3,4, 5,5,6,6,6, 8,8,8,10 6 · 3⤊ 1⤋
2x + y = 2
1x - y = 7
---------------- add these two equations to get:
3x = 9
x = 3
Then, from either of your original equations, you can determine y:
x - y = 7
x - 7 = y
3 - 7 = y
y = -4
2006-09-14 09:32:15 · answer #5 · answered by Dave_Stark 7 · 2⤊ 1⤋
well first you should figure out how to spell solve.
2006-09-14 09:34:13 · answer #6 · answered by Rebecca 3 · 0⤊ 1⤋
I'll give you x=3
Someone else will give you y.
2006-09-14 09:29:04 · answer #7 · answered by Anonymous · 1⤊ 0⤋
with two variables, there is no set answer
2006-09-14 09:30:31 · answer #8 · answered by arctic storm 1 · 0⤊ 5⤋