#1**0 **

[ 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

CPhill
Mar 7, 2017

#2**+5 **

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.

Julius
Mar 7, 2017