Answer: second option.
Step-by-step explanation:
In order to solve this exercise, it is necessary to remember the following properties of logarithms:

In this case you have the following inequality:

So you need to solve for the variable "x".
The steps to do it are below:
1. You need to apply
to both sides of the inequality:

2. Now you must apply the properties shown before:

3. Then, rounding to the nearest ten-thousandth, you get:

380 divide by 20
it will take her 19 hours to stamp 380 letters
Answer:
Your answer is D.
Step-by-step explanation:
If you need explanation ask me in comment
Answer:
8
Step-by-step explanation:
100 = x^2 + AC^2
17^2 = AC^2 + (21 - x)^2
289 = AC^2 + 21^2 + x^2 - 2*21*x
289 =<u> AC^2</u> + 441 +<u> x^2</u> - 42x
from 1st equation AC^2 + x^2 = 100
289 = 441 + 100 - 42x
289 = 541 - 42x
42x = 541 - 289 = 252
x = 252/42 = 6
so AC^2 = 100 - 6^2 = 100 - 36 = 64
AC = 8
EQUATION OF A CIRCLE = (x-h)² + (y-k)² =r²
Since the center of the cercle is in O, then h=5 & k=-2
(x-5)² + (y+2² =9