Answer:
-51
Step-by-step explanation:
cheggs acc
0.10x - 0.08x = 250 - 185
0.02x = 65
x = 3250
Find the powers 
$a^{2}=5+2 \sqrt{6}$
$a^{3}=11 \sqrt{2}+9 \sqrt{3}$
The cubic term gives us a clue, we can use a linear combination to eliminate the root 3 term $a^{3}-9 a=2 \sqrt{2}$ Square $\left(a^{3}-9 a\right)^{2}=8$ which gives one solution. Expand we have $a^{6}-18 a^{4}-81 a^{2}=8$ Hence the polynomial $x^{6}-18 x^{4}-81 x^{2}-8$ will have a as a solution.
Note this is not the simplest solution as $x^{6}-18 x^{4}-81 x^{2}-8=\left(x^{2}-8\right)\left(x^{4}-10 x^{2}+1\right)$
so fits with the other answers.
Answer:
95%.
Step-by-step explanation:
We have been given that the lifetimes of light bulbs of a particular type are normally distributed with a mean of 370 hours and a standard deviation of 7 hours.
We are asked to find the percentage of the bulbs whose lifetimes lie within 2 standard deviations to either side of the mean using empirical rule.
The empirical rule (68-95-99.7) states that approximately 68% of data points lie within 1 standard deviation of mean and 95% of data points lie within two standard deviation of mean. 99.7% of data points lie within three standard deviation of mean.
Therefore, approximately 95% of data points lie within two standard deviation of mean.
