4/10 = x/6 i don't know how to get x. can someone me.

This problem using cross multiplication, so basically, you're just multiplying in a big X. It's easier to look at it when it's written across, so I added a picture to help guide you. The colored arrows show you what two values to multiply.

So here, you're multiplying 4 and 6, and then 10 and x. 

4x6 = 24 and 10 times x = 10x

The next step is to isolate the variable. To do so, you must use the opposite operation that the "x" is involved in. Here we have 10x (x is multiplied to 10) so we must divide. 1x = x, so we want to divide 10x by a number that will make 10 = 1.

Well, 10/10 is 1, so divide 10x by 10, to cancel the 10 out, and leave you with just "x." What you do to one side of the equal sign, you must do to the other, so divide 24 by 10 as well.

24 / 10 = x < this should be how your equation looks at this point.
Solve for 24/10, and your answer will equal x.

24 / 10 = 2.4 < this is your x.

2.4 = x