Answer:
-16/35
Step-by-step explanation:
To know tha answer for this, you have to find the prime factor of 15 and 21:
Prime factor of 15: 3, 5
Prime factor of 21: 3, 7
Therefore, the LCD (least common denominator) of 15 and 21 are: 3 * 5 * 7 = 105
-14/15+10/21
= -14*7/15*7 + 10*5 / 21*5
= -98/105 + 50/105
= -48/105
Simplify:
= -16/35
Hope this help you :3