Answer:
(
7
n+
3
) (
n
+
7
)
Step-by-step explanation:
factor by grouping
Using the normal distribution, it is found that there is a 0.877 = 87.7% probability of a bulb lasting for at most 569 hours.
<h3>Normal Probability Distribution</h3>
The z-score of a measure X of a normally distributed variable with mean
and standard deviation
is given by:

- The z-score measures how many standard deviations the measure is above or below the mean.
- Looking at the z-score table, the p-value associated with this z-score is found, which is the percentile of X.
The mean and the standard deviation are given, respectively, by:

The probability of a bulb lasting for at most 569 hours is the <u>p-value of Z when X = 569</u>, hence:


Z = 1.16
Z = 1.16 has a p-value of 0.877.
0.877 = 87.7% probability of a bulb lasting for at most 569 hours.
More can be learned about the normal distribution at brainly.com/question/24663213
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Answer:
114
Step-by-step explanation:
550*12%=66
400*12%=48
48+66=114
<em>when we solve the equation it will become
x</em>² + 9x<em>= 0
now here a = 1 , b = 9 and c = 0
by using quaderatic formula
x = -b +,-</em>√<em>b </em>²<em>- 4ac / 2a ( 2a is divided by all terms )
by putting values
x = - 9 +,</em><em>- </em>√<em>81 / 2(1) ( </em>√<em>81 = 9)</em><em>
x = -9 + 9 / 2 and x = -9 -9 /2
x = 0 and x = -18 /2 = -9
now there are two values for x one is- 9 and other is 0
so we put -9 as the value of x then answer will be zero..</em>