I believe the answer is C, x-3.
There are 12 inches in a foot, so 9ft = 108in. Also, 80% = 0.8. Therefore the formula is:
h(n) = 108 * 0.8^n.
To find the bounce height after 10 bounces, substitute n=10 into the equation:
h(n) = 108 * 0.8^10 = 11.60in (2.d.p.).
Finally to find how many bounces happen before the height is less than one inch, substitute h(n) = 1, then rearrage with logarithms to solve for the power, x:
108 * 0.8^x = 1;
0.8^x = 1/108;
Ln(0.8^x) = ln(1/108);
xln(0.8) = ln(1\108);
x = ln(1/108) / ln(0.8) = -4.682 / -0.223 = 21 bounces
Q) Without a calculator, we must estimate the value of the following expression:
![3-\sqrt[]{38}.](https://tex.z-dn.net/?f=3-%5Csqrt%5B%5D%7B38%7D.)
A) I estimate 3 - √38 to be approximately -3.2.
First, we estimate the value of √38. √38 is between √36 and √49, but close to √36 (since 38 is closer to 4 than it is to 9). Since √36 is 6, √38 is probably something like 6.1 or 6.2. Filling 6.2 in the expression and simplifying, we have this:

So, I expect the number 3 - √38 to be close to -3.2.
Using a calculator we find that: 3 - √38 ≅ -3.16, which it is approximately the result that we found.
Answer
Without a calculator we find that 3 - √38 ≅ -3.2.
Answer:
The price elasticity of demand is calculated as the percentage change in quantity divided by the percentage change in price.