10 is not a multiple of 3 so no 6/10 is not multiples for 3/10 and 6 is not a mutiple of 10 so it can't be also the same with 6/30 although 6/30 is multiples for 3 but 6 is not a mutiple for 10.
I think it is y=-.25
7*3 - 4y = 20
21 - 4y = 20
subtract 21 from each side
- 4y = - 1
divide each side by - 4
y= -.25
