Question 186474
15/3y - (-80/10x)
5/y +8/x
You cannot directly add fractions that have different denominators.

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lcd = xy
Rewrite each fraction with the lcd as its denominator:

5x/lcd + 8y/lcd

Add to get:

(5x + 8y)/lcd

= (5x+8y)/xy
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Cheers,
Stan H.