If the random variable x is normally distributed, percent of all possible observed values of x will be within three standard deviations of the mean. 68.26 95.44 99.73 100 none of these

99.73

Step-by-step explanation:

Problems of normally distributed samples are solved using the z-score formula.

In a set with mean and standard deviation , the zscore of a measure X is given by:

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

Percentage within 3 standard deviations of the mean.

pvalue of Z = 3 subtracted by the pvalue of Z = -3.

Z = 3 has a pvalue of 0.9987

Z = -3 has a pvalue of 0.0013

0.9987 - 0.0013 = 0.9974 = 99.74%

A small rounding difference, but the answer is:

99.73

5x+40

5(x + 8)

7x - 49

7(x - 7)

18x + 9

9(2x + 1)

15x - 10

5(3x - 2)

step-by-step explanation:

for number one all you have to do is factor 5 out of 5x + 40

for number 2 factor 7 out of 7x - 49

for number three factor 9 out of 18x + 9

for number four factor 5 out of 15x - 10