SOLUTION: If the system 2x-5y=1 and -3x+7y=-3 is to be solved by elimination of x, and the first equation is multiplied by 3, then by which number should the second equation be multiplied?

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Question 6678: If the system 2x-5y=1 and -3x+7y=-3 is to be solved by elimination of x, and the first equation is multiplied by 3, then by which number should the second equation be multiplied?
*I think that the answer is 2.Is this correct?
Found 2 solutions by xcentaur, ichudov:
Answer by xcentaur(357)   (Show Source): You can put this solution on YOUR website!
Multiplying equation by-
2x-5y=1....[*3]
-3x+7y=-3..[*2]

Adding both equations after multiplication,we get-
6x - 15y = 3
-6x + 14y =-6
-------------
y = -3
-------------


y=-3
Substituting this value in [1] we get,
2x-5y=1
2x-5(-3)=1
2x+15=1
2x=-14
x=-7


x=-7,y=-3
-Prabhat
Answer by ichudov(507)   (Show Source): You can put this solution on YOUR website!
you are fully right, that way the coefficients in front of x would be the same except for the sign. you can then add them and eliminate x.

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