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2 years ago

Evaluate: 3x^2 + y when x=1 and y=-3 *

Mathematics

1 answer:

Sliva [168]2 years ago

4 0

Answer:

Step-by-step explanation:

x=1 and y=-3

so 3x^2 + y = 3*1^2 + (-3)

= 3* 1 -3

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Solve for k:<br> 310 – (30 x 7) = 5 x k

tester [92]

Answer:

k=20

Step-by-step explanation:

ph*tomath (the app) is your friend btw because this would be really easy to solve using that but

solve for k:

simplify the left side as 310-210 then =100

so 100=5k

divide by 5 and k=20

7 0

2 years ago

I’ll give u brainiest pls help me im so lost

Vlad1618 [11]

Answer:

(f o g)(4)=27

Step-by-step explanation:

(f o g)(4)=2x+5

f(g(4))=2x+5

f(4²-2(4)+3)=2x+5

f(16-8+3)=2x+5

f(8+3)=2x+5

f(11)=2x+5

f(11)=2(11)+5

f(11)=22+5

f(11)=27

Therefore, (f o g)(4)=27

3 0

2 years ago

#10 i The table shows the admission costs (in dollars) and the average number of daily visitors at an amusement park each the pa

lions [1.4K]

The line of best fit is a straight line that can be used to predict the

average daily attendance for a given admission cost.

Correct responses:

The equation of best fit is; $\underline{ \hat Y = 1,042 - 4.9 \cdot X_i}$

The correlation coefficient is; r ≈<u> -0.969</u>

<h3>Methods by which the line of best fit is found</h3>

The given data is presented in the following tabular format;

$\begin{tabular}{|c|c|c|c|c|c|c|c|c|}Cost, (dollars), x&20&21&22&24&25&27&28&30\\Daily attendance, y&940&935&940&925&920&905&910&890\end{array}\right]$

The equation of the line of best fit is given by the regression line

equation as follows;

$\hat Y = \mathbf{b_0 + b_1 \cdot X_i}$

Where;

$\hat Y$ = Predicted value of the<em> i</em>th observation

b₀ = Estimated regression equation intercept

b₁ = The estimate of the slope regression equation

$X_i$ = The <em>i</em>th observed value

$b_1 = \mathbf{\dfrac{\sum (X - \overline X) \cdot (Y - \overline Y) }{\sum \left(X - \overline X \right)^2}}$

$\overline X$ = 24.625

$\overline Y$ = 960.625

$\mathbf{\sum(X - \overline X) \cdot (Y - \overline Y)} = -433.125$

$\mathbf{\sum(X - \overline X)^2} = 87.875$

Therefore;

$b_1 = \mathbf{\dfrac{-433.125}{87.875}} \approx -4.9289$

Therefore;

The slope given to the nearest tenth is b₁ ≈ -4.9

$b_0 = \mathbf{\dfrac{\left(\sum Y \right) \cdot \left(\sum X^2 \right) - \left(\sum X \right) \cdot \left(\sum X \cdot Y\right)} {n \cdot \left(\sum X^2\right) - \left(\sum X \right)^2}}$

By using MS Excel, we have;

n = 8

∑X = 197

∑Y = 7365

∑X² = 4939

∑Y² = 6782675

∑X·Y = 180930

(∑X)² = 38809

Therefore;

$b_0 = \dfrac{7365 \times 4939-197 \times 180930}{8 \times 4939 - 38809} \approx \mathbf{1041.9986}$

The y-intercept given to the nearest tenth is b₀ ≈ 1,042

The equation of the line of best fit is therefore;

$\underline{\hat Y = 1042 - 4.9 \cdot X_i}$

The correlation coefficient is given by the formula;

$\displaystyle r = \mathbf{\dfrac{\sum \left(X_i - \overline X) \cdot \left(Y - \overline Y \right)}{ \sqrt{\sum \left(X_i - \overline X \right)^2 \cdot \sum \left(Y_i - \overline Y \right)^2} }}$

Where;

$\sqrt{\sum \left(X - \overline X \right)^2 \times \sum \left(Y - \overline Y \right)^2} = \mathbf{446.8121}$

$\sum \left(X_i - \overline X \right) \times \left(Y - \overline Y\right) = \mathbf{-433.125}$

Which gives;

$r = \dfrac{-433.125}{446.8121} \approx \mathbf{-0.969367213}$

The correlation coefficient given to the nearest thousandth is therefore;

<u>Correlation coefficient, r ≈ -0.969</u>

Learn more about regression analysis here:

brainly.com/question/14279500

7 0

2 years ago

1.the ratio if the weight of an object on mars to its weight in earth is 9 to 25.If a person weighs 120pouns on earth,how much w

Ilya [14]

Question #1
$\frac{9}{25}=\frac{x}{120}\\\\120(9) = 25x\\\\1080 = 25x\\\\x= 43.2$

For #1, the answer is 43.2

Question #2
$\frac{6}{5} = \frac{2580}{x} \\\\2580(5) = 6x\\\\12900 = 6x\\\\x = 2150$

For #2, the answer is 2150

8 0

2 years ago

The figure shows a carpeted room. How many square feet of the room is carpeted?

alukav5142 [94]

Answer:

Step-by-step explanation:

So split it into two shapes. Two rectangles.

Rectangle 1 = 4 * 5 = 20

Rectangle 2 = 2 * 10 = 20

20 + 20 = 40

6 0

3 years ago

Read 2 more answers