x − y = − 5
y = −2x − 4
I m trying to find the solution between these two equations. When I move over the X (from the top equation) to the other side of the equal sign so I can use the elimination method, would I get rid of the negative sign next to the Y or would I keep it?
Can you help me with this math problem?
2018-01-10 12:50 pm
回答 (4)
2018-01-10 1:06 pm
Method 1 : Substitution
x - y = -5 …… [1]
y = -2x - 4 …… [2]
Substitute [2] into [1] :
x - (-2x - 4) = -5
x + 2x + 4 = -5
3x + 4 = -5
3x = -9
x = -3
Substitute x = -3 into [2] :
y = -2(-3) - 4
y = 2
Hence, (x, y) = (-3, 2)
====
Method 2 : Elimination
x - y = -5 …… [1]
y = -2x - 4 …… [2]
From [2] :
2x + y = -4 …… [3]
[1] + [3] :
x + 2x - y + y = -5 - 4
3x = -9
x = -3
Substitute x = -3 into [2] :
y = -2(-3) - 4
y = 2
Hence, (x, y) = (-3, 2)
x - y = -5 …… [1]
y = -2x - 4 …… [2]
Substitute [2] into [1] :
x - (-2x - 4) = -5
x + 2x + 4 = -5
3x + 4 = -5
3x = -9
x = -3
Substitute x = -3 into [2] :
y = -2(-3) - 4
y = 2
Hence, (x, y) = (-3, 2)
====
Method 2 : Elimination
x - y = -5 …… [1]
y = -2x - 4 …… [2]
From [2] :
2x + y = -4 …… [3]
[1] + [3] :
x + 2x - y + y = -5 - 4
3x = -9
x = -3
Substitute x = -3 into [2] :
y = -2(-3) - 4
y = 2
Hence, (x, y) = (-3, 2)
2018-01-10 6:03 pm
x - y = - 5
2x + y = - 4________add
3x = - 9
x = - 3
- 6 + y = - 4
y = 2
x = - 3 , y = 2
2x + y = - 4________add
3x = - 9
x = - 3
- 6 + y = - 4
y = 2
x = - 3 , y = 2
2018-01-10 1:40 pm
Yes I can help you on your math question!
Now you must give me the best answer and 10 points.
I am the only one who answered there question you asked, remember you asked "Can you help me with this math problem?" everyone else did not answer your question . words matter and I love logic.
Now you must give me the best answer and 10 points.
I am the only one who answered there question you asked, remember you asked "Can you help me with this math problem?" everyone else did not answer your question . words matter and I love logic.
2018-01-10 1:19 pm
x − y = − 5
y = −2x − 4
x = −2x − 9
3x = −9
x = −3, y = 2
y = −2x − 4
x = −2x − 9
3x = −9
x = −3, y = 2
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