4x+3y=neg.1
x-2y=30
2006-06-09 14:10:17 · 7 answers · asked by lovinmymatt 2 in Science & Mathematics ➔ Mathematics
4x+3y=-1
-4x+8y=-120
11y=-121
y=-11
x-2(-11)=30
x+22=30
x=8
2006-06-09 14:14:25 · answer #1 · answered by buildingadesertx 2 · 0⤊ 0⤋
I don't think i can solve by addition, but I can solve by subtraction.
(1) 4x+3y=(-1)
(2) x-2y=30
Multiply equation (2) on both sides by 4 and subtract...
(1) 4x+3y=(-1)
(2) 4x-8y=120
becomes (3) 11y = 119.
Thus y = 10 9/11.
Now, substitute y as 10 9/11 in equation (1)...
(1) 4x+30 27/11=(-1)
becomes (1) 4x+32 5/11 = -1.
(1) 4x+32 5/11 = -1
(1) 4x = -33 5/11
Therefore, x equals -8 4/11.
hmm...
I must have done soemthing wrong...
Oh I see...
It becomes -121 instead of 119. Silly me! Now the equation becomes 11y = -121, or y = -11.
This now becomes much easier...
x - 2(-11) = 30
x + 22 = 30
x = 8
2006-06-09 21:34:29 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Add the equations
5x+y=29
Isolate X
x=30+2y
Solve for Y
5(30+2y)+y=29
150+11y=29
11y= -121
y= -11
Solve for X.
x-2(-11)=30
x+22=30
x=8
y=-11
x=8
2006-06-09 21:55:33 · answer #3 · answered by mini_roller 3 · 0⤊ 0⤋
4x + 3y = -1
  x  - 2y = 30
 4x + 3y = -1
-4x + 8y = -120
-------------------------
        11y = -121
y = 11
x - 2(11) = 30
x = 42
2006-06-09 21:49:52 · answer #4 · answered by Anonymous · 0⤊ 0⤋
4x+3y=-1-------(1)
x-2y=30---------(2)
(2)x4-------------->4x-8y=120
4x+3y=-1
--------------------
-11y=121
--------------------
y=121/-11
y=-11
substituting in eq(2)
x-2(-11)=30
x+22=30
x=30-22
x=8
x=8, y=-11
2006-06-10 02:45:01 · answer #5 · answered by K N Swamy 3 · 0⤊ 0⤋
buildingades is right! you go girl!
2006-06-09 22:21:30 · answer #6 · answered by Anonymous · 0⤊ 0⤋
^Agree
2006-06-09 21:17:09 · answer #7 · answered by joossa 3 · 0⤊ 0⤋