SOLUTION: Can someone help me on this? I need to solve: 3x/7 - 5x/3 = 2/21 Thanks, Adriana

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Question 54913: Can someone help me on this?
I need to solve: 3x/7 - 5x/3 = 2/21
Thanks,
Adriana
Answer by rapaljer(4671) About Me  (Show Source):
You can put this solution on YOUR website!
Multiply both sides by the LCD, which is 21:
+3x%2F7+-+5x%2F3+=+2%2F21
21%2A%28+3x%2F7%29+-+21%2A%285x%2F3%29+=+21%2A%282%2F21%29

The nice thing is that ALL the denominators divide out:
+3%2A3x+-+7%2A5x+=+2
9x+-35x+=+2
-26x=2

Divide both sides by -26:
%28-26x%29%2F%28-26%29+=+2%2F%28-26%29+

x=-1%2F13

Sometimes life comes out even, sometimes it does not. In this case it looks like it does NOT!

R^2 at SCC