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artcher [175]
1 year ago
6

13....................

Mathematics
1 answer:
Mashcka [7]1 year ago
6 0

13.

(a)

y=-5x^2+21x-3

for x = 2:

y=-5(2)^2+21(2)-3=-20+42-3=19

for x = 5

y=-5(5)^2+21(5)-3=-125+105-3=-23

(b)

The graph is:

(c)

Using the graph:

\begin{gathered} x=1.8,y=18.6 \\ x=0.548,y=7 \\ x=3.65,y=7 \end{gathered}\begin{gathered} x=1.8 \\ y=-5(1.8)^2+21(1.8)-3=-16.2+37.8-3=18.6 \end{gathered}\begin{gathered} y=7 \\ -5x^2+21x-3=7 \\ -5x^2+21x-10=0 \end{gathered}

Using the quadratic formula:

\begin{gathered} x=\frac{-b\pm\sqrt[]{b^2-4ac}}{2a} \\ x=\frac{-21\pm\sqrt[]{21^2-4(-5)(-10)}}{2(-5)} \\ x=\frac{-21\pm\sqrt[]{241}}{-10} \\ x=0.54758 \\ or \\ x=3.6524 \end{gathered}

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Answer:

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Step-by-step explanation:

This is because -9 is LESS than -3, when you add or subtract using negative numbers, such as 7-9, you get -2. However when you subtract 7-13, you get -6. Because you subtracted a greater number from 7, your answer is -6 is LESS than -2. This is the same with inequalities, greater negative numbers will always be smaller and smaller negative numbers will always be greater.

Hope this helps!

4 0
1 year ago
IQ scores on the WAIS test approximate a normal curve with a mean of 100 and a standard deviation of 15. What IQ score is identi
riadik2000 [5.3K]

Answer:

IQ scores of at least 130.81 are identified with the upper 2%.

Step-by-step explanation:

Normal Probability Distribution:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean \mu and standard deviation \sigma, the z-score of a measure X is given by:

Z = \frac{X - \mu}{\sigma}

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 p-value, we get the probability that the value of the measure is greater than X.

Mean of 100 and a standard deviation of 15.

This means that \mu = 100, \sigma = 15

What IQ score is identified with the upper 2%?

IQ scores of at least the 100 - 2 = 98th percentile, which is X when Z has a p-value of 0.98, so X when Z = 2.054.

Z = \frac{X - \mu}{\sigma}

2.054 = \frac{X - 100}{15}

X - 100 = 15*2.054

X = 130.81

IQ scores of at least 130.81 are identified with the upper 2%.

7 0
3 years ago
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gladu [14]

Answer:

C)

Step-by-step explanation:

- π can be added to π to get a rational number

π + (-π) = 0

0 is a rational number

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3 years ago
Some wanna look at this and help me ?​
Vika [28.1K]
21x+1+14x+4=180
35x+5=180
35x=175
X=5
21(5)+1
105+1
Answer
4 0
3 years ago
In a survey of 400 seniors, x percent said that they plan on majoring in physics. One university has used this data to estimate
azamat

Answer:

2 percent

Step-by-step explanation:

We can use two separate fractions, one representing the amount of physics majors expected and the amount of seniors expected in physics majors by the university.

\frac{400x}{66} = \frac{400}{3600}

Now cross multiply.

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2 years ago
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