Question 565619: Use the system to answer the question
{x+3y=6}
{4x + 6y = -6}
Note: The problem above are both under the { symbol, the first one is over the second one.
These are the choices for the problem
(-9, 5)
(-3, 3)
(6, 3)
(12, -2)
I'm not sure how I got it wrong. The correct answer was the first one. (I have the answers, so I can redo the ones I missed, but I have to show my work, and I don't know how to get that answer.) Could you look over my work that I did and explain how to get the solution? Thanks, much appreciated.
My Work:
{x+3y=6}
{4x + 6y = -6}
1. I multiply the first equation by -4 so I can eliminate the 4x
(-4) {x+3y=6} + {-4x -12y = -24}
2. I eliminate the 4x from the problem
{-4x - 12y = -24}
{4x + 6y = -6}
(-4 and 4 crosses out so I'm left with"
0x - 12y = -24
0x + 6y = -6
3. Then I solve:
-12 and a + 6 gets a -6. -24 and -6 gets -18
so I get 0x -6y = -18
From there I am stuck. I'm not sure if I use substitution or elimination or what.
Thanks for your help!
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! {x+3y=6}
{4x + 6y = -6}
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Multiply thru the 1st equation by 2:
2x + 6y = 12
4x + 6y = -6
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Subtract and solve for "x":
2x = -18
x = -9
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Solve for "y":
x + 3y = 6
-9 + 3y = 6
3y = 15
y = 5
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Solution: (-9,5)
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Cheers,
Stan H.
These are the choices for the problem
(-9, 5)
(-3, 3)
(6, 3)
(12, -2)
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