SOLUTION: PLEASE HELP ME FIND THE ANSWER TO: 7X+15Y=39 X-3Y=-20 THE CHAPTER IS CALLED SOLVING SYSTEMS USING ELIMINATION

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Question 101900This question is from textbook PRENTICE HALL MATHEMATICS ALGEBRA 1
: PLEASE HELP ME FIND THE ANSWER TO: 7X+15Y=39 X-3Y=-20
THE CHAPTER IS CALLED SOLVING SYSTEMS USING ELIMINATION This question is from textbook PRENTICE HALL MATHEMATICS ALGEBRA 1

Answer by checkley75(3666) About Me  (Show Source):
You can put this solution on YOUR website!
7X+15Y=39
X-3Y=-20 NOW MULTIPLY THIS EQUATION BY 5 AND ADD THE 2 EQUATIONS
5X-15Y=-100
7X+15Y=39
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12X=-61
X=-61/12 ANSWER.
-61/12-3Y=-20
-3Y=-20+61/12
-3Y=(-240+61)/12
-3Y=-179/12
-Y=(-179/12)/-3
Y=(-179/12)(-1/3)
Y=179/36 ANSWER.
PROOF
7(-61/12)+15(179/36)=39
-427/12+2685/36=39
(3*-427+2685)/36=39
(-1281+2685)/36=39
1404/36=39
39=39