Answer:
x = 12
length = 4 cm
width = 20 cm
Step-by-step explanation:
a = lw
Plug in the givens
80 = (x - 8)(x + 8)
Multiply
80 = x^2 - 64
Add 64 to both sides
144 = x^2
Take the square root of both sides
x = ±12
(The negative root is extraneous since the dimensions can not be negative)
x = 12
length = x - 8 = 4 cm
width = x + 8 = 20 cm
To solve this problem you must apply the proccedure shown below:
1. You must make a system of equation by using the information given in the problem above. Then, let's call:
: The number of computers sold.
: The number of hard drives sold.
2. Therefore, you have the following system of equations:
2. Solve for in the first equation and substitute it into the second equation:
3. Solve for :
4. Substitute the value of into the first equation to calculate :
Therefore, the answer is: The store sold 
computers and 
hard drives.
Answer:
f(3) = 68
Step-by-step explanation:
→ f(1) = 2 ⇒ f(2) = f²(2 − 1) + 4
= f²(1) + 4
= 2² + 4
= 8
………………………………………………
→ f(2) = 8 ⇒ f(3) = f²(3 − 1) + 4
= f²(2) + 4
= 8² + 4
= 64 + 4
= 68
