Because this is a fourth degree that will be tricky to factor as it is, we will do a u substitution. Let . We can now rewrite that polynomial in terms of u:
. Filling into the quadratic formula we have
. Simplifying down
and
or
. That means that u = 8 or u = -1. But don't forget that we let
, so we have to put x-squared back in for u. That gives us
which simplifies down to
. That also gives us
. When we take the square root of -1, we have to use the fact that -1 = i^2, so we sub that in to get
. All in all, your solutions are as follows:
which is choice b.
A train is traveling from New Orleans to Memphis at a constant speed of 79 mph. New Orleans and Tennessee are 395.1 miles apart.
1 answer:
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24 is the numerical coefficient
1.06 is the base of the power with exponent t
Answer:
The interval [32.6 cm, 45.8 cm]
Step-by-step explanation:
According with the <em>68–95–99.7 rule for the Normal distribution:</em> If is the mean of the distribution and s the standard deviation, around 68% of the data must fall in the interval
around 95% of the data must fall in the interval
around 99.7% of the data must fall in the interval
So, the range of lengths that covers almost all the data (99.7%) is the interval
[39.2 - 3*2.2, 39.2 + 3*2.2] = [32.6, 45.8]
<em>This means that if we measure the upper arm length of a male over 20 years old in the United States, the probability that the length is between 32.6 cm and 45.8 cm is 99.7%</em>