Hi!
Algebraic expression. First thing to do is write some variables.
Set o = the original price of an item, and n to the new cost of the item.
Since the item is 25% off, you subtract 25% of itself from it's original cost, to get the new cost. That's written out as:
n = o - 1/4o
Now to fully simplify this. o, is technically 1 * o. So what is 1/4 subtracted from 1? 3/4. The equation therefore becomes:
n = 3/4o
Hope this helped!