Question 1180164: -x + 3y = 2 and x - 5y = -4 Solving for Two Variables using Elimination
Found 3 solutions by mananth, MathTherapy, ikleyn:
Answer by mananth(16949)   (Show Source):
You can put this solution on YOUR website!
-1 x + 3 y = 2
1 x + -5 y = -4
Eliminate y
multiply (1)by 5
Multiply (2) by 3
-5 x 15 y = 10
3 x -15 y = -12
Add the two equations
-2 x = -2
/ -2
x = 1
plug value of x in (1)
-1 x + 3 y = 2
-1 + 3 y = 2
3 y = 3
y = 1
Ans x = 1
y = 1
Answer by MathTherapy(10703)  (Show Source):
You can put this solution on YOUR website!
-x + 3y = 2 and x - 5y = -4 Solving for Two Variables using Elimination
It'd be NICE if this person could be BANNED from this forum.
What he/she did to this problem was TOTALLY and UNEQUIVOCALLY silly, UNNECESSARY and outright STUPID.
- x + 3y = 2 ------ eq (i)
x - 5y = - 4 ---- eq (ii)
From the onset ALL ONE NEEDS to DO is ADD the 2 equations to get: - 2y = - 2 ===> 
Then, substitute 1 for y in eq (ii) to get a value of 1 for x, also.
Answer by ikleyn(53570)  (Show Source):
You can put this solution on YOUR website! .
-x + 3y = 2 and x - 5y = -4 Solving for Two Variables using Elimination
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I write it, because I do not agree with the procedure, which @mananth uses in his solution.
As the equations are given, there is a straightforward way to proceed, without making unnecessary calculations.
You will get the same answer, but will not do unnecessary job.
-x + 3y = 2, (1)
x - 5y = -4. (2)
As equations are given, you are lucky, because equations ARE JUST READY for elimination.
Add equations (1) and (2). The terms '-x' and 'x' will cancel each other, so you will get
3y + (-5y) = 2 + (-4),
-2y = -2, y = (-2)/(-2) = 1.
Then from equation (2)
x = -4 + 5y = -4 + 5*1 = -4 + 5 = 1.
ANSWER. The solution is x = 1, y = 1.
Solved in a way as it should be done and as it is expected to be done.
If you will solve following to @mananth's way, the teacher will make squared eyes
and will consider your job as if you are mentally blind and do not see the simplest way.
In the next instance, the teacher will understand, that you were indoctrinated
by an Artificial Intelligence in its, still not perfect, mode.
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I do understand PERFECTLY, why @mananth selected that way.
It is because his computer code, which he uses as an Artificial Intelligence,
is programmed this way.
It does not seek for the best way or for most reasonable way.
In this sense, his computer code is not a perfect tool for teaching.
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