Final answer:
To rewrite the fractions (13/15) and (9/10) with a common denominator, find the LCM of the denominators, which is 30. Therefore, (13/15) becomes (26/30) and (9/10) becomes (27/30). Both fractions are now written with a common denominator, allowing further operations.
Step-by-step explanation:
To rewrite (13)/(15) and (9)/(10) so that they have a common denominator, we first need to find the least common multiple (LCM) of the two denominators, 15 and 10. The LCM of 15 and 10 is 30. Now we multiply both the numerator and denominator of each fraction by the number needed to get the denominator to 30. For (13)/(15), we multiply by 2 to make the denominator 30, so it becomes (26)/(30). For (9)/(10), we multiply by 3 to make the denominator 30, so it becomes (27)/(30).
Now both fractions have the common denominator of 30, and they can be easily compared, added, or subtracted. Remember that when finding a common denominator, we never add denominators; we find a common multiple and adjust the numerators accordingly.