Write the fractions with a comment denominator then determine it they are equivalent 8/10 and 12/15 6/8 and 8/12 3/9 and 4/8 7/4 and 9/5 15/12 and 20/16 15/9 and 30/18 how do you answer this i don't get it pls anyone

I believe you mean common denominator. A denominator is the bottom part of a fraction or what something is "out of". If it has a common denominator it means they have the same denominator. 
1. 8/10 12/15. They both have a common denominator of 30. You have to multiply the numerator by the denominator. 8/10*3/3= 24/30 and 12/15*2/2=24/30. A lot simpler way to do that is reduce them. 8/10 divided by 4 = 4/5. 12/15 divided by 3/3 = 4/5.
They are the same.
2. 3/4 and 2/3 when reduces. Or 6/8*3/3= 18/24. 8/12*2= 16/24. NOT equivalent
3.3/9*8/8= 24/72         4/8*9/9= 36/72 NOT equivalent
4.7/4*5/5= 35/20          9/5*4/4= 36/20 NOT equivalent
5.15/12*4/4= 60/48     20/16*3/3= 60/48 Equivalent
6.15/9*2/2= 30/18 and 30/18 is the other number. Equivalent

Hope this helps!

I posted this on your other question also!