Answer:
The half life of the car is 3.98 years.
Step-by-step explanation:
The value of the car after t years is given by the following equation:
In which V(0) is the initial value and r is the constant decay rate, as a decimal.
The value of a certain car decreases by 16% each year.
This means that 
So
What is the 1⁄2-life of the car?
This is t for which V(t) = 0.5V(0). So
The half life of the car is 3.98 years.
Circumference = 2 x radius x Pi
Circumference = 2 x 0.8 x pi
Circumference = 1.6pi or 5.024 yards
area = r^2 x pi
Area = 0.8^2 x pi
Area = 0.64pi or 2.0096 square yards
The equation 5/2 - x + x - 5/x + 2 + 3x + 8/x^2 - 4 = 0 is a quadratic equation
The value of x is 8 or 1
<h3>How to determine the value of x?</h3>
The equation is given as:
5/2 - x + x - 5/x + 2 + 3x + 8/x^2 - 4 = 0
Rewrite as:
-5/x - 2 + x - 5/x + 2 + 3x + 8/x^2 - 4 = 0
Take the LCM
[-5(x + 2) + (x -5)(x- 2)]\[x^2 - 4 + [3x + 8]/[x^2 - 4] = 0
Expand
[-5x - 10 + x^2 - 7x + 10]/[x^2 - 4] + [3x + 8]/[x^2 - 4] = 0
Evaluate the like terms
[x^2 - 12x]/[x^2 - 4] + [3x + 8]/[x^2 - 4 = 0
Multiply through by x^2 - 4
x^2 - 12x+ 3x + 8 = 0
Evaluate the like terms
x^2 -9x + 8 = 0
Expand
x^2 -x - 8x + 8 = 0
Factorize
x(x -1) - 8(x - 1) = 0
Factor out x - 1
(x -8)(x - 1) = 0
Solve for x
x = 8 or x = 1
Hence, the value of x is 8 or 1
Read more about equations at:
brainly.com/question/2972832
15$ I believe, as we can disregard the two original books (they have been payed for) leaving her to buy 1 book and having seven dollars, however if she needs $8 more you simply need to add 8+7.
$15.00 * 20% = $15.00 * 0.2 = $3.<span>00
the answer is </span>$3.<span>00</span>
