Answer: x - 0.40x which simplifies to 0.60x
Reason
40% in decimal form is 0.40
0.40x represents 40% of some number x.
Subtract that from x to end up with what is shown above.
The 0.60 refers to the idea if you get a 40% discount, then you pay the remaining 60%
Example:
The item starts out at x = 100 dollars.
You save 40% of x = 0.40x = 0.40*100 = 40 dollars
You pay 100-40 = 60 dollars, or you could compute it like this: 0.60x = 0.60*100 = 60