SOLUTION: what multiplier should be used for each of the following equations to eliminate one unknown by subtraction? 3x- y=7 , 2x+7y=42

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Question 53332: what multiplier should be used for each of the following equations to eliminate one unknown by subtraction? 3x- y=7 , 2x+7y=42
Answer by venugopalramana(3286) About Me  (Show Source):
You can put this solution on YOUR website!
what multiplier should be used for each of the following equations to eliminate one unknown by subtraction?
3x- y=7 ......................1
2x+7y=42............................2
WE WANT TO ELIMINATE X SAY...EQN.1 HAS 3 AS COEFFICIENT OF X.EQN.2 HAS 2 AS COEFFICIENT OF X.THEIR LCM IS 6..SO MULTIPLY EQN.1 WITH 6/3=2 AND EQN.2 ITH 6/2 = 3 AND UBTRACT ONE FROM THE OTHER ..THAT IS 2*EQN.1 - 3*EQN.2 WILL ELIMINATE Y
SIMILARLY IF WE WANT TO ELIMINATE Y THEN
7*EQN.1 + EQN.2 WILL LIMINATE Y .