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Question 310872: Solve the system by the elimination method.
5x+3y=-11
7x-2y=13
Thank you to whoever can help me.
Answer by mollukutti(30)   (Show Source):
You can put this solution on YOUR website! Basic Facts:
For elimination method, coefficients of one of the variables i.e, x or y needs to be equalized first
In this case we will try to equalize the co-efficients of x
5x+3y=-11 ..... multiply the expressions on either sides by 7
7x-2y=13 ..... multiply the expressions on either sides by 5
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35x + 21y = -77........ now let us subtract the left hand side expression and the
35x - 10y = 65......... right hand side expression
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(35x + 21y)-(35x - 10y) = (-77)-65
or, 35x + 21y - 35x + 10y = -77 -65
or, 35x - 35x + 21y +10y = -142
or, 31y = -142
or, y = -142/31
By substitution we find the value of x now
7x - 2y = 13
or, 7x - 2. -142/31 = 13
or, 7x + 284/31 = 13
or, 7x = 13 - 284/31
or 7x = 119/31
or, x = 17/31 (dividing either sides by 7)
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