We are given f(x) = 5x
and we are to find inverse of f(x).

Step 1:
Replace f(x) by y.
So,

y = 5x

Step 2:
Isolate x
So,

x = y/5

Step 3:
Replace x by f'(y)
So,

f'(y) = y/5

Step 4:
Replace all occurrences of y by x.
So,

f'(x) = x/5

Therefore, the inverse of f(x) = 5x is f'(x) = x/5

7 0

3 years ago

Amy received a $80 gift card for a coffee store. She used it in buying some coffee that cost $8.24 per pound. After buying the c

SVEN [57.7K]

Answer:

5 pounds

Step-by-step explanation:

Given that:

Amount of gift card = $80

Cost of coffee per pound = $8.24

Amount left in the card = $38.80

To find:

Number of pounds of coffee bought = ?

Solution:

Let the number of pounds of the coffee bought = $x$ pounds

Cost of 1 pound = $8.24

Cost of $x$ pounds = $8.24 $\times x$

Writing the equation as per question statement:

$80 - 8.24x = 38.80\\\Rightarrow 80 - 38.80 = 8.24x\\\Rightarrow 8.24x = 41.2\\\Rightarrow x = \dfrac{41.2}{8.24}\\\Rightarrow \bold{x = 5\ pounds}$

Therefore, 5 pounds of coffee was bought.

3 0

3 years ago