Question 203697: I keep having issues with these type of problems. Please help!
x+5y= 9
3x- y=-5
Thank you!!
Answer by RAY100(1637)   (Show Source):
You can put this solution on YOUR website! 1) x+5y = 9,,,,,or x=9-5y
2) 3x -y =-5
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using substitution,,,subst (1) into (2)
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3(9-5y) -y = -5
27 -15y -y = -5
-16y = -32
y= 2
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subst in (1),,,x= 9 -5(2) = -1
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check,,,(1) (-1) +5(2) = 9,,,,ok
(2) 3(-1) -(2) = -5,,,,,ok
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another technique is to multiply equations until adding or substracting them eliminates one variable
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Multiply (2) by 5,,,(2) 15x-5y = -25
(1) x+5y=9
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adding (1) + (2),,,,16x = -16,,,,x=-1
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subst in (1) (-1) +5y = 9,,,5y = 10,,,y=2
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the other technique is to graph both and note intersection.
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Have a good day
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