8 = x divided by 12.8 means this:
8 =

To solve for x, we need to get rid of the denominator, 12.8.
To do that, we need to cancel it out by multiplying by 12.8.
Multiply both sides by 12.8.
8 * 12.8 = 102.4.

* 12.8 = x
We are now left with:
x = 102.4
I hope this helps!