SOLUTION: Solve by the elimination method. 7r+3s=38 3r+7s=66 ----------- -- 21r+9s =114 21r-49= 462 58/576 S=? 9.9....? ----------- -- 7r-3(?)=? R=? It doesn’t make sense to me. C

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Question 203405: Solve by the elimination method.
7r+3s=38
3r+7s=66
--------------
21r+9s =114
21r-49= 462
58/576
S=? 9.9....?
--------------
7r-3(?)=?
R=?
It doesn’t make sense to me. Can you please help me solving this problem?
Thank you!

Answer by jsmallt9(3758)   (Show Source): You can put this solution on YOUR website!
Solve by the elimination method.
7r+3s=38
3r+7s=66
--------------
21r+ 9s = 114
21r+49s = 462

Except for the "-" in front of the 49 and the missing "s" after the 49, you are good so far. Now we can subtract the second equation from the first one. As a result, the 21r terms will cancel which is the key to the Elimination Method. After subtracting we have:

Now we solve this equation. Divide by -40:

Now we substitute this value in for "s" into one of the original equations:


Multiply by 10 to eliminate the fraction:

Subtract 261 from both sides:

Divide by 70:

So the solution is
r = 17/10 and s = 89/10
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