Got this question on an assignment, not asking for homework answers or anything but...
21x + 12y = 84
7x + 4y -28 = 0
it seems like the same equation, so how do we solve it, or answer it?
Thanks.
21x + 12y = 84
7x + 4y -28 = 0
it seems like the same equation, so how do we solve it, or answer it?
Thanks.
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You can't solve for a specific (x,y) solution; as you say, these two equations are equivalent, so you have one equation and two unknowns.
But you can solve for x = -(4/7)y + 4
And you can solve for y = -(7/4)x + 7
And... that's as far as you can go!
But you can solve for x = -(4/7)y + 4
And you can solve for y = -(7/4)x + 7
And... that's as far as you can go!
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Its done like
http://en.wikipedia.org/wiki/System_of_l…
Because it is the same equation, the system is underdetermined.
http://en.wikipedia.org/wiki/Underdeterm…
So you just have to express y via x or vice versa from one of the equations, and you are done with the assignment. The other variable is arbitrary real number.
http://en.wikipedia.org/wiki/System_of_l…
Because it is the same equation, the system is underdetermined.
http://en.wikipedia.org/wiki/Underdeterm…
So you just have to express y via x or vice versa from one of the equations, and you are done with the assignment. The other variable is arbitrary real number.
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Both the equations are same.... so for one equation u cannot have only one value of x and y
there may be multiple value...
putting x=0 we get y=7
putting x=1 we get y=21/4
putting x=2 we get y=7/2
.....
.....
.....
and so on...
again
putting y=0 we get x=7
putting y=1 we get x=24/7
putting y=2 we get x=20/7
.....
.....
.....
and so on...
so there cannot be any particular solution for these equations as they both are same....
there may be multiple value...
putting x=0 we get y=7
putting x=1 we get y=21/4
putting x=2 we get y=7/2
.....
.....
.....
and so on...
again
putting y=0 we get x=7
putting y=1 we get x=24/7
putting y=2 we get x=20/7
.....
.....
.....
and so on...
so there cannot be any particular solution for these equations as they both are same....
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It certainly does look like the same equation. This will only work if X equals Y. And it can't be zero. Any number other than zero will work, but the main idea is that X=Y here.
[EDIT] lazy turtle minused the 28 to the other side of the = when he should have added it.
[EDIT] lazy turtle minused the 28 to the other side of the = when he should have added it.
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As previous answerer said it is sme equation and only answers you get are sets of ordered pairs for x and y that solve either (actually both) equations
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They are the same question, they have a common multiple, divide the top one by 3 and you would get the bottom one. Are you just suppose to graph it? There are no values you give us for x or y
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21x + 12y = 84 (a)
7x + 4y = -28 (b)
times (b) by 3
21x + 12y = -84
(a) - (b) =
21x + 12y = 84
21x + 12y = -84
````````````````````````
I see what you mean :S
7x + 4y = -28 (b)
times (b) by 3
21x + 12y = -84
(a) - (b) =
21x + 12y = 84
21x + 12y = -84
````````````````````````
I see what you mean :S
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You're right...
Its the same equation... So you can solve for x and y since you've got insufficient data.
Its the same equation... So you can solve for x and y since you've got insufficient data.