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valina [46]
3 years ago
10

I’m Dum And Clueless Help

Mathematics
1 answer:
emmainna [20.7K]3 years ago
7 0

Answer:

-3a-4b+5

Step-by-step explanation:

(3a-6b+12)-(6a-2b+7)

3a-6b+12-6a+2b-7

3a-6a-6b+2b+12-7

-3a-4b+5

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Suppose that an automobile manufacturer designed a radically new lightweight engine and wants to recommend the grade of gasoline
yawa3891 [41]

Answer:

B) 4.07

Step-by-step explanation:

First we need to calculate the mean of all the data, which is the same as the mean of the means of each grade of gasoline:

Regular    BelowRegular   Premium   SuperPremium

39.31             36.69                38.99             40.04

39.87            40.00                40.02             39.89

39.87            41.01                  39.99             39.93

X1⁻=39.68    X2⁻= 39.23       X3⁻= 39.66    X4⁻=  39.95

Xgrand⁻ = (39.68+39.23+39.66+39.95)/4 = 39.63

Next we need to calculate the sum of squares within the group (SSW) and the sum of squares between the groups (SSB), and the respective degrees of freedom):

SSW = [ (39.31-39.68)² + (39.87-39.68)² + (39.87-39.68)² ] + [ (36.69-39.23)² + (40.00-39.23)² + (41.01-39.23)² ] + [ (38.99-39.66)² + (40.02-39.66)² + (39.99-39.66)² ] + [ (40.04-39.95)² + (39.89-39.95)² + (39.93-39.95)² ] = [0.2091] + [10.2129] + [0.6874] + [0.0121] = 11.12

SSW =  11.12

Degrees of freedom in this case is calculated by m(n-1), with m being the number of grades of gasoline (4) and n being the number of trial results for each one (3), so we would have 4(3-1) = 8 degrees of freedom

SSB = [ (39.68-39.63)² + (39.68-39.63)² + (39.68-39.63)²] + [ (39.23-39.63)² + (39.23-39.63)² + (39.23-39.63)² ] + [ (39.66-39.63)² + (39.66-39.63)² + (39.66-39.63)² ] + [ (39.95-39.63)² + (39.95-39.63)² +(39.95-39.63)² ] = [0.0075] + [0.48] + [0.0027] + [0.3072] = 0.7974

SSB =  0.80

For this case, the degrees of freedom are m-1, so we would have 4-1 = 3 degrees of freedom

Now we can establish the hypothesis for the test:

H0: μ1 = μ2 = μ3 = μ4

The null hypothesis states that the means of miles per gallon for each fuel are the same, indicating that the drade of gasoline does not make a difference, therefore our alternative hypothesis will be:

H1: the grade of gasoline does makes a difference

We will use the F statistic to test the hypothesis, which is calculated like follows:

F - statistic = (SSB/m-1) / (SSW/m(n-1)) = (0.80/3) / (11.12/8) = 0.19

We know that the level of significance we are using is α = 0.05, so to find the critical value F we need to look at some table of critical values for the F distribution for the 0.05 significance level (like the attached image). Then we just need to look fot the value that is located in the intersection between the degrees of freedom we have in the numerator (horizontal) and the denominator (vertical) of the statistic (3 and 8). That critical value is:

Fc = 4.07

3 0
3 years ago
The position of an object at time t is given by s(t) = 1 - 12t. Find the instantaneous velocity at t = 2 by finding the derivati
yulyashka [42]

The change of displacement with respect to time is defined as speed. Velocity is a vector quantity. The instantaneous velocity at t = 2 is -12.

<h3>What is velocity?</h3>

The change of displacement with respect to time is defined as Velocity. velocity is a vector quantity. It is a time-based component. Its standard unit is m/sec.

Given that the position of an object at time t is given by s(t) = 1 - 12t. Therefore, the velocity of the object can be written as,

V = ds/dt

   = d(1 - 12t)/dt

   = -12

s'(t) = -12

Now, the instantaneous velocity at t=2 is,

s'(2) = -12

Hence, the instantaneous velocity at t = 2 is -12.

To learn more about Velocity:

brainly.com/question/862972

#SPJ1

5 0
2 years ago
Two common names for streets are FirstFirst Street and MainMain ​Street, with 14 comma 86614,866 streets bearing one of these
oksian1 [2.3K]

Answer:  There are 7,677 streets named as " First Street" and 7, 189 streets named as  "Main Street" .

Step-by-step explanation:

Let x be the number of streets named as First Street .

y be the number of streets named as Main Street.

AS per the given information, we have the following system of equations :

x+y=14866-------------(1)\\\\x=488+y-------------(2)

Substitute the value of x from (2) in (1) , we get

488+y+y=14866\\\\ 2y =14866- 488\\\\ 2y=14378\\\\ y=7189

Put value of y in (2), we get

x=488+7189=7677

Hence , there are 7,677 streets named as " First Street" and 7, 189 streets named as  "Main Street" .

6 0
3 years ago
Determine the quotient of 1 and 1 over 3 divided by 3 over 5.
natita [175]
1 1/3 divided by 3/5= 2 2/9. Hope this helps :)
4 0
3 years ago
A first number plus twice a second number is 9. Twice the first number plus the second totals 21. Find the numbers
WITCHER [35]
Let x and y be the numbers;
We have x + 2y = 9 and 2x + y = 21;
Then, x = 9 - 2y;
Finally, 2(9-2y) + y = 21 ;
18 - 4y + y = 21;
18 - 3y = 21;
-3y = 3;
y = - 1;
x = 9 - 2× (-1);
x = 9 + 2 ;
x = 11;
7 0
3 years ago
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