Answer:
x1, x2 = 4.74 , -2.74
Step-by-step explanation:
To find the roots of a quadratic function we have to use the bhaskara formula
ax^2 + bx + c
x^2 - 2x - 13
a = 1 b = -2 c = -13
x1 = (-b + √ b^2 - 4ac)/2a
x2 =(-b - √ b^2 - 4ac)/2a
x1 = (2 + √ (2^2 - 4 * 1 * (-13)))/2 * 1
x1 = (2 + √ (4 + 52)) / 2
x1 = (2 + √ 56 ) / 2
x1 = (2 + 7.48) / 2
x1 = 9.48 / 2
x1 = 4.74
x2 = (2 - √ (2^2 - 4 * 1 * (-13)))/2 * 1
x2 = (2 - √ (4 + 52)) / 2
x2 = (2 - √ 56 ) / 2
x2 = (2 - 7.48) / 2
x2 = -5.48 / 2
x2 = -2.74
I think b...i’m wrong pretty sure..
Answer:
And we can find this probability using the complement rule:
And in order to find these probabilities we can find tables for the normal standard distribution, excel or a calculator.
Step-by-step explanation:
Previous concepts
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
Solution to the problem
Let X the random variable that represent the scores of a population, and for this case we know the distribution for X is given by:
Where and
We are interested on this probability
And the best way to solve this problem is using the normal standard distribution and the z score given by:
If we apply this formula to our probability we got this:
And we can find this probability using the complement rule:
And in order to find these probabilities we can find tables for the normal standard distribution, excel or a calculator.
Answer: Should be 5(9)+4
Step-by-step explanation: