It's D, because the mean doesn't matter as much if it's only taken in a small variability. The mean was selected from 25 random pages in the book, that is why it is right.
1234567890233572o7o5y345uo22u.3936584643728284/43794729237932972478864966666666666666666666666666666666663870434573428734907 goood luck!
Answer:

Step-by-step explanation:
The time constant of the isotope is:


The decay of the isotope is described by the following model:

Now, the time is cleared in the equation:



Answer: B
Begin by simplifying the given equation, so it's rearranged into standard form. Move all the terms onto one side, so they equal 0. This would result with
-3x-9=0. Quadratic formula is (-b±√(b²-4ac))/(2a). Standard form follow this variable format:
+bx+c. Use the numbers that correspond with each variable to substitute them into the quadratic formula. This would be
(-(-3)±√(-3²-4(4)(-9)/2(4).