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Question
When solving a rational equation, why is it all right to remove the denominator by multiplying both sides by the LCD and why can you not do the same operation when simplifying a rational expression?
Hello Eva
When you deal with and EQUATION, you can do whatever you want as long as it's done on both sides. What you get is an equivalent equation because the equality still holds.
When you deal with an EXPRESSION, you have a number (which maybe have constants and variables) and therefore you cannot arbitrarily multiply or divide by anything because that CHANGES the number you have. The only thing you can do is multiply AND divide by another number, because that is equivalent to multiplying by 1.
Hope this is clear.
Cheers,
David
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Answers by Expert:
David Montiel
Expertise
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Experience
Over 8 years of private tutoring in Math and Physics. Five years as a Teaching Assistant in Physics.
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BSc in Chemical Engineering.
MSc in Chemical Physics.
PhD in Physics.
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