Question 184248: Explain why you might need to multiply each equation by a different number when solving a system by Elimination. Explain why.
Answer by jeselle(2)   (Show Source):
You can put this solution on YOUR website! to eliminate one of the variables,
in the process of elimination,you can either use addition or subtraction
and for you to eliminate one variable,for example,variables x and y,
then you want to eliminate x,the coefficient of x in the two equations must be the same but must have opposite signs if you'll use addition(to zero out the 2 x's from the 2 equation) or the same signs for subtraction(the sign of the subtrahend is changed to its opposite when performing subtaction)
because you cannot give a value to both variables at the same time,
so you must eliminate one then you'll obtain a value for the other
and then you'll substitute that value to any of the two equations to get the value of the other variable
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