SOLUTION: solve by substitution I need help finding the response to these sentences 2m+n=16 m-3n=15

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Question 289137: solve by substitution
I need help finding the response to these sentences
2m+n=16
m-3n=15
Found 2 solutions by jim_thompson5910, stanbon:
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
2m%2Bn=16 Start with the first equation.


n=-2m%2B16 Subtract 2m from both sides.


m-3n=15 Move on to the second equation.


m-3%28-2m%2B16%29=15 Plug in n=-2m%2B16


m%2B6m-48=15 Distribute.


7m-48=15 Combine like terms on the left side.


7m=15%2B48 Add 48 to both sides.


7m=63 Combine like terms on the right side.


m=63%2F7 Divide both sides by 7 to isolate m.


m=9 Reduce.


n=-2m%2B16 Go back to the previously isolated equation.


n=-2%289%29%2B16 Plug in m=9


n=-18%2B16 Multiply -2 and 9 to get -18


n=-2 Add -18 to 16 to get -2


So the solutions are m=9 and n=-2

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
2m+n=16
m-3n=15
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Comment: It's up to you to decide which variable
you are going to eliminate.
If you want to eliminate the "n" terms,
Multiply thru the 1st equation by 3, then add the two equations:
6m + 3n = 48
m - 3n = 15
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7m = 63
m = 9
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Substitute into either of the original equations and solve for "n":
9-3n = 15
-3n = 6
n = -2
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Cheers,
Stan H.
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