You mean 8% of x gives you 12.75?
Place the percentage number over 100 first. This will give us:
(8/100) * x = 12.75
We want to isolate the x on the left side with a coefficient of 1. So to get rid of the denominator, which is 100, multiply both sides by 100 to cancel it out.
100 * (8/100) * x = 12.75 * 100
8x = 1275
Dividing both sides by 8, we will get:
x = 1275/8
You can do long division to figure this out, but I was able to do this in my head, and I got: x = 159.625.