SOLUTION: 3x + y = 2 and 2x-y=3

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Question 113239: 3x + y = 2 and 2x-y=3
Found 2 solutions by MathLover1, bucky:
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

3x+%2B+y+=+2 and
2x+%96+y+=+3
------------------------ we can solve this system by substitution or by addition
Let do it by substitution:
the first equation, we can solve in terms of y
3x+%2B+y+=+2………move 3xto the right
+y+=+-+3x+%2B+2
Now, substitute y in second equation
2x+%96+y+=+3
2x+%96+%28-+3x+%2B+2%29+=+3
2x+%2B+3x+%96+2+=+3…….move -2 to the right

+5x++=+3+%2B+2…….
+5x++=+5…….
+x++=+1…….
Now, find y
+y+=+-+3x+%2B+2
+y+=+-+3%2A1+%2B+2
+y+=+-+3+%2B+2
+y+=+-+1+

Answer by bucky(2189) About Me  (Show Source):
You can put this solution on YOUR website!
Given the two equations:
.
3x + y = 2
2x - y = 3
.
This pair of equations is "nicely" arranged for solving by variable elimination because
one of the terms in the top equation [that term is +y] is equal but with the opposite
sign to the corresponding term in the bottom equation [that term is -y]. If you add these
two equations vertically, the y-column will disappear because +y added to -y cancels
out.
.
In the x column the 3x adds to the 2x and equals 5x. As we mentioned, in the y column the
+y and the -y sum to zero and therefore are gone. And on the other side of the equal sign
the +2 and the +3 add to 5. So, after adding the two equations vertically you are left
with 5x = 5. You can solve this equation for x by dividing both sides of this equation by
5 (the multiplier of the x) and you get:
.
x = 5/5 = 1
.
So you now know that x = 1
.
You can then go back to either one of the two equations you were given and replace x by 1
in that equation and then solve for y. Let's go back to the first equation:
.
3x + y = 2
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replace x by 1 and the equation becomes:
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3(1) + y = 2
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do the multiplication of 3 times 1 and the equation reduces to:
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3 + y = 2
.
Get rid of the 3 on the left side by subtracting 3 from both sides of the equation to
reach the solution:
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y = 2 - 3 = -1
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So the solution to this problem is x = 1 and y = -1
.
Hope this helps you to understand the problem a little better.
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