Answer:
B) 34/48
Step-by-step explanation:
The easiest common denominator to find is the product of the denominators you have.
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The difference is ...

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<em>Additional comment</em>
The difference numerator and denominator have a common factor of 2, so can be reduced to 17/24. The denominator 24 could have been used as the common denominator from the start.
5/6 -1/8 = 20/24 -3/24 = 17/24 . . . . reduced result
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Using the <em>least common denominator</em> does not always result in a reduced sum or difference. If some other denominator is used (as here), then you can be assured that the result will need to be reduced to get to lowest terms.
3xy + 10xy - 5x + 2x - 2yx
Add 3xy to 10xy
13xy - 5x + 2x - 2yx
Add -5x to 2x
Final Answer: B.) 13xy -3x - 2yx
5/12=10/24 and 7/8= 21/24, add those and you will get 31/24 subtract 31 from24 and get 7 your new fraction is 1 7/24 that is 5/12 + 7/8 in simplest form