SOLUTION: Adding and subtracting unlike rational expressions. HELP!! I have read and re-read the examples and directions and still can't figure out how to do this. Thank you. subtraction.

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: Adding and subtracting unlike rational expressions. HELP!! I have read and re-read the examples and directions and still can't figure out how to do this. Thank you. subtraction.      Log On


   

Question 73075: Adding and subtracting unlike rational expressions. HELP!! I have read and re-read the examples and directions and still can't figure out how to do this. Thank you.
subtraction..
2 over 5w-10 minus 3 over 2w-4
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
2 over 5w-10 minus 3 over 2w-4
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It's like this; if I say 3 buicks minus 2 fords you
might very well say Yah??? That would mean you can't
subtract the way I stated the problem.
But, if I said 3 buicks minus 2 buicks you could say
" 1 buick" and I would agree that was an acceptable
answer.
Similarly you can't directly subtract 2/3 from 5/8.
They are not the same animals. What you do is create
a "common denominator"; then you can subtract.
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Now, your problem:
2/(5(w-2)) - 3/(2(w-2))
These have a least common denominator of 15(w-2)
So convert each of the fractions; write each with the lcd as its denominator:
[2*3]/lcd - [3*5]/lcd
6/lcd - 15/lcd
=-9/[15(w-s)]
=-3/[5(w-5)]
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Cheers,
Stan H.
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