This is the eqn of a str line. <span>y+4=12/7(x-1) would be clearer if written as
</span><span>y+4=(12/7)(x-1). y+4 = (12/7)x - 12/7.
Multiply all terms by 7 to remove the fractions: 7(y+4) = 12x - 12.
Complete the multiplication: 7y + 28 = 12x - 12.
Arrange the x and y terms on the left side and the constants on the right:
-12x + 7y = -40. This is standard form. Some people might disagree and say that -12x + 7y + 40 is standard form. They are equivalent.
</span>
Answer:
(a) 
(b) 83.6%
Step-by-step explanation:
(a)
A least square regression line is to be formed for predicting beak heat loss, as a percent of total body heat loss, from temperature.
Use MS-Excel to form the regression line.
Go to Data → Data Analysis → Regression
A dialog box will open.
Select the X and Y variables.
Press OK.
The regression output is attached below.
The equation of the least‑squares regression line is:

(b)
The coefficient of determination R² specifies the percentage of the variance in the dependent variable (Y) that is forecasted or explained by linear regression and the forecaster variable (X, also recognized as the independent variable).
Consider the regression output attached below.
The R² value is 0.8360.
That is 83.6% of the variation in beak heat loss is explained by the straight‑line relationship with temperature.
The answer to the question is
20/30. 24/30,. 21/30
"The sum of two numbers is 20" can be translated mathematically into the equation:
x + y = 20.
"... and their difference is 10" can be translated mathematically as:
x - y = 10
We can now find the two unknown numbers, x and y, because we now have a system of two equations in two unknowns, x and y. We'll use the Addition-Subtraction Method, also know as the Elimination Method, to solve this system of equations for x and y by first eliminating one of the variables, y, by adding the second equation to the first equation to get a third equation in just one unknown, x, as follows:
Adding the two equations will eliminate the variable y:
x + y = 20
x - y = 10
-----------
2x + 0 = 30
2x = 30
(2x)/2 = 30/2
(2/2)x = 15
(1)x = 15
x = 15
Now, substitute x = 15 back into one of the two original equations. Let's use the equation showing the sum of x and y as follows (Note: We could have used the other equation instead):
x + y = 20
15 + y = 20
15 - 15 + y = 20 - 15
0 + y = 5
y = 5
CHECK:
In order for x = 15 and y = 5 to be the solution to our original system of two linear equations in two unknowns, x and y, this pair of numbers must satisfy BOTH equations as follows:
x + y = 20 x - y = 10
15 + 5 = 20 15 - 5 = 10
20 = 20 10 = 10
Therefore, x = 15 and y = 5 is indeed the solution to our original system of two linear equations in two unknowns, x and y, and the product of the two numbers x = 15 and y = 5 is:
xy = 15(5)
xy = 75
The perimeter is 320. Just multiply 80 times 4