Answer:
7.  6/8 & 7/8 
8. 8/12 & 3/12
Step-by-step explanation:
For number 7, the LCD is 8. 
So, 
 *
 * 
 = (3*2)/(4*2) = 6/8
 = (3*2)/(4*2) = 6/8
For number 8, the LCD is 12.
So, 
(2/3) = (2/3) * (4/4) = (2*4) / (3*4) = 8/12
(1/4) = (1/4) * (3/3) = (1*3) / (4*3) = 3/12
Hope this helps u!!
If it did, let me know and leave a thanks:))