Astore has 40 percent off sale on headphones with this discounted price of one pair

Since there is a 40% discount, this means that they subtracted 40% of the original price from the original price, meaning that $36 is 60% of the original price. We can use ratios to figure out the original price (so 100% of the price).

100% x
60% 36

x = 36*100 / 60 = 3600 / 60 = 360 / 6 = 60

We can check this quickly: 60 * 0.4 (or 40%) is 24. If we subtract 60-24 we get 36, so we did the problem correctly

8x

Step-by-step explanation:

Using differentiation from first principles

f'(x) =  

      =

      =  

      =

      = ← cancel the h on numerator/denominator

      = 4(2x)

      = 8x