Step-by-step explanation:
This one cannot be factorized so to find the roots, use the quadratic formula.
The answer is 360 million or 720 million cells after 4 hours of doubling.
4.02x9=36.18 that's the answer
Answer:

Step-by-step explanation:
The z-score tells us how many standard deviations a value is away from the mean.
The formula is:

where x is the value,
is the mean, and s is the standard deviation.
We want to find the z-score for the score of an 83, the mean is 72, and the standard deviation is 5.

Substitute the values into the formula.

Solve the numerator.

Divide.

The z-score is 2.2, which means the score of 83 is 2.2 standard deviations above the mean.