Answer:
(-4,0) and (4,0)
Step-by-step explanation:
The x-intercepts occur for values of x where f(x) = 0.
f(x) = 0 when the nominator () = 0.
is a difference of squares,
so you can factor it as (x + 4)(x – 4)
When x = –4 or x = 4, the nominator is 0, and f(x) = 0
Answer:
15.39% of the scores are less than 450
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.
In this problem, we have that:
What percentage of the scores are less than 450?
This is the pvalue of Z when X = 450. So
has a pvalue of 0.1539
15.39% of the scores are less than 450