1. (2r + 9)(2r-9) = 4r^2 -81
+ (2r - 9)^2 = 4r^2 - 36r + 81
= 8r^2 - 36r
2. 12 - 5 [ a^2 + a - 1 ] + 5a
= 12 - 5a^2 - 5a + 5 +5a
= 17 - 5a^2
x^3 + 3x^2 + 6x + 18
______
3. x-3/ x^4 + 7
- ( x^4 - 3x^3)
----------------
3x^3 + 7
- (3x^3 - 6x^2)
-------------------
6x^2 + 7
- (6x^2 - 18x)
-------------------
18x + 7
- (18x - 54)
--------------
7 + 54 = R = 61
welp That's What I get
Answer:nbcmbcvd
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Step-by-step explanation:
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Answer:
20 days
Step-by-step explanation:
It takes 12 men 5 days to complete a job. Work out how many days it would take 3 men to complete the same job.
12 * 5 = 60
60/3 = 20
It will take 3 men 20 days to do the same job
Answer:
25 cm^2
Step-by-step explanation:
Area = (height * base)/2
(5 * 10) / 2 = 25 cm^2
Answer:
The unexplained variance would be 100-90.25 % = 9.75. And that correspond to the percentage of the dependent variable in the correlation is due purely to chance
Step-by-step explanation:
Previous concepts
Pearson correlation coefficient(r), "measures a linear dependence between two variables (x and y). Its a parametric correlation test because it depends to the distribution of the data. And other assumption is that the variables x and y needs to follow a normal distribution".
In order to calculate the correlation coefficient we can use this formula:
On this case we got that r =-0.95
In order to find the % of variance explained by the model we need to calculate the determination coefficient given by:

And that means this : "90.25% of the variation of y is explained by the variation in x"
So then the unexplained variance would be 100-90.25 % = 9.75. And that correspond to the percentage of the dependent variable in the correlation is due purely to chance