[ 3y - 8 ] / 12 = y / 5 cross-multiply
5 [3y - 8 ] = 12y simpify
15y - 40 = 12y add 40 to both sides. subtract 12y from both sides
3y = 40 divide both sides by 3
y = 40 / 3
I know this has question has been answered, but I wanted to show you this neat trick I use for cross multiplying:
For Example: 8/4=x/10
For this I would use a method called the oval circle method:
Basically you oval a diagonal with only numbers no letters and circle the remaining number. And the letter will go
as your x=. So we oval 8 and 10 and circle 4. And we make x as x=. And we plug into the formula: x=aXb/c
So it becomes x= 8 X 10/4
x=80/4
x=20.
But I suppose it wont work for this problem, but it's extremely simple and easy way to do it.