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3 years ago

Use Vieta's Theorem to solve the problems.

Mathematics

1 answer:

VladimirAG [237]3 years ago

4 0

Answer:

The answer is -2, -17

Step-by-step explanation:

You write a system of equations

$x_{1} +x_{2}=-19\\x_{1}-x_{2}=15$

Then you solve:

-2, -17

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If the coefficient of determination is 0.25 and the sum of squares residual is 180, then what is the value of SSY?

Gennadij [26K]

Answer:

And then $SSY=SS_{total}=\sum_{j=1}^n (y_j-\bar y)^2 =240$

C. 240

Step-by-step explanation:

Previous concepts

Analysis of variance (ANOVA) "is used to analyze the differences among group means in a sample".

The sum of squares "is the sum of the square of variation, where variation is defined as the spread between each individual value and the grand mean"

When we conduct a multiple regression we want to know about the relationship between several independent or predictor variables and a dependent or criterion variable.

If we assume that we have $k$ independent variables and we have $j=1,\dots,j$ individuals, we can define the following formulas of variation:

$SS_{total}=\sum_{j=1}^n (y_j-\bar y)^2$

$SS_{regression}=SS_{model}=\sum_{j=1}^n (\hat y_{j}-\bar y)^2$

$SS_{error}=\sum_{j=1}^n (y_{j}-\hat y_j)^2 =180$

And we have this property

$SST==SSY=SS_{regression}+SS_{error}=SSR+180$

If we solve for SSR we got:

$SSR= SSY-180$ (1)

And we know that the determination coefficient is given by:

$R^2 = \frac{SSR}{SSY}$

We know the value os $R^2= 0.25$ and we can replace SSR in terms of SSY with the equation (1)

$R^2 =0.25= \frac{SSY-180}{SSY}= 1-\frac{180}{SSY}$

And solving SSY we got:

$\frac{180}{SSY}=1-0.25=0.75$

$SSY= \frac{180}{0.75}=240$

And then $SSY=SS_{total}=\sum_{j=1}^n (y_j-\bar y)^2 =240$

C. 240

7 0

3 years ago

Express the decimal 2.39 as a percent. <br> A. 23.9% <br> B. 240% <br> C. .239% <br> D. 239%

Assoli18 [71]

Solve:-

2.39 = decimal

2.39 × 100 = 239
239%

2.39 = C. 239%

6 0

3 years ago

Read 2 more answers

A sound wave enters a new medium where sound travles faster. How does this affect the frequency and wavelength of the sound?

zhenek [66]

Answer:

The frequency doesn't change. If the wavespeed increases, then the wavelength must also increase ... It's just the distance the wave travels during each complete wiggle.

Step-by-step explanation:

Sound waves are a type of mechanical wave which requires a material medium for transmission. The transmission of such waves occurs as a result of vibration of particles in the material medium. The faster the vibration of the particles the higher the speed of the sound waves.

When a sound enters a new medium where the sound travels faster, it means the vibration of particles is high, and the wavelength of the waves increases which means the speed of the wave has increased. The frequency on the other hand will remain constant.

4 0

3 years ago

Show that line passing through points (3,-2) and (-4,-2) is a horizontal line

Ierofanga [76]

Step-by-step explanation:

horizontal lines will have a gradient(m) of 0

so if m=0 , the line is horizontal

formula to find m:

m=y2-y1 / x2-x1

insert coordinates into formula

$m = \frac{ - 2 - ( - 2)}{ - 4 - 3} \\ \\ m = \frac{ - 2 + 2}{ - 7} \\ m = \frac{0}{ - 7} \\ m = 0$

As m=0 , therefore it is a horizonta line.

hope this helps..

3 0

2 years ago

NEED HELP ASAP!!!

Sergeeva-Olga [200]

Answer:

(b) $P(\textrm{Event of getting a 3 in the spinner)} = \frac{11}{61}$

Step-by-step explanation:

Let E: Event of getting a 3 in the spinner.

So, the number of favorable outcomes = 11

Total number of outcomes = Number of times the outcomes is {1,2,3,4,5,6}

= {13 +10 +11+16+11} = { 61}

So, the total number of outcomes = 61

$\textrm{Probability of Event E} = \frac{\textrm{Number of favorable events}}{\textrm{Total number of outcomes}}$

So, here $P(\textrm{Event of getting a 3 in the spinner)} = \frac{11}{61}$

3 0

2 years ago