SOLUTION: I need to solve this my elimination method 7r-3s=33 3r+7s=39 I tried to solve using the example given but my answer makes absolutely no sense! Help!

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Question 494836: I need to solve this my elimination method
7r-3s=33
3r+7s=39

I tried to solve using the example given but my answer makes absolutely no sense! Help!
Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
your equations are:

7r - 3s = 33 (first equation)
3r + 7s = 39 (second equation)

multiply first equation by 3 to get:
21r - 9s = 99 (third equation)

multiply second equation by 7 to get:
21r + 49s = 273 (fourth equation.

your equations are now:

21r - 9s = 99 (third equation)
21r + 49s = 273 (fourth equation)

subtract third equation from fourth equation to get:

58s = 174
divide both sides of this equation by 58 to get:
s = 3

substitute for s in the first equation to get:
7r - 3s = 33 (first equation) becomes:
7r - 9 = 33
add 9 to both sides of this equation to get:
7r = 42
divide both sides of this equation by 7 to get:
r = 6

you have:
r = 6
s = 3

substitute for r and s in the second equation to get:

3r + 7s = 39 (second equation) becomes:
18 + 21 = 39
combine like terms to get:
39 = 39

this confirms that the values for r and s are good.

the answer to this problem is:
r = 6
s = 3