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3 years ago

Which of the following are solutions to the equation below? Check all that apply. x2 + x - 20 = 0

Mathematics

2 answers:

Mila [183]3 years ago

7 0

Δ = 1 + 4*20 = 81
x' = (-1 + 9)/2 = 4
x'' = (-1 - 9)/2 = -5
4² + 4 - 20 = 0
(-5)² - 5 - 20 = 0
Ok !

erastova [34]3 years ago

6 0

Answer:-5 and 4

Step-by-step explanation:

apex

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Which value is the solution to the equation -8 = 6 - 7x? <br>A. -7 <br>B. - 2 <br>C. 2 <br>D. 5

r-ruslan [8.4K]

Step-by-step explanation:

the answer is c: 2..............

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3 years ago

Based on historical data, your manager believes that 40% of the company's orders come from first-time customers. A random sample

Vedmedyk [2.9K]

Answer:

$P(0.26 \leq p \leq 0.43)=0.7204-0.0032=0.7172$

Step-by-step explanation:

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".

The population proportion have the following distribution

$p \sim N(p=0.4,\sqrt{\frac{p(1-p)}{n}}=\sqrt{\frac{0.4(1-0.4)}{91}}=0.0514)$

And we can solve the problem using the z score on this case given by:

$z=\frac{p_o -p}{\sqrt{\frac{p(1-p)}{n}}}$

We are interested on this probability:

$P(0.26 \leq p \leq 0.43)$

And we can use the z score formula, and we got this:

$P(\frac{0.26 -0.4}{\sqrt{\frac{0.4(1-0.4)}{91}}} \leq Z \leq \frac{0.43 -0.4}{\sqrt{\frac{0.4(1-0.4)}{91}}})$

$P(-2.726 \leq Z \leq 0.584)$

And we can find this probability like this:

$P(-2.726 \leq Z \leq 0.584)=P(Z$

7 0

3 years ago

Help me idk how to do this

ElenaW [278]

To do this, you have to plug each x value into the rule.

1.y = 15 - 3×2
y = 15 - 6
y = 9

So the first y value would be 9.

2.y = 15 - 3×3
y = 15 - 9
y = 6

3. y = 15 - 3×4
y = 15-12
y = 3

4. y = 15 - 3×5
y = 15-15
y = 0

Hope this helps!

3 0

4 years ago

In a sample of 77 children , the mean age as at which they first began to combine words was 16.51 months

astraxan [27]

Answer:

Mean age = 1271.27

Step-by-step explanation:

No of children = 77

The age at which children first began to combine words = 16.51 months

Mean age = No of children × age at which children first began to combine words

= 77 × 16.51

= 1271.27

Mean age = 1271.27

7 0

3 years ago

Help.me if u can need it

Whitepunk [10]

The correct answer answer 56

3 0

3 years ago

Read 2 more answers