What's happening is that every subtraction can be written as "addition of the opposite."
18-5 = 18 + (-5)
One reason this is done in the work you showed is that they're trying to show why you distribute the negative and the 1 into the parentheses, why you multiply everything in the parentheses by "-1" and not just 1.
The other reason is to later to be able to move the individual terms around, so you'll be able to combine like terms.
When you move terms around, the sign has to stay attached to the term, so writing all the subtractions as addition helps keep the sign attached.
Answer: 
Step-by-step explanation:
Given
lies in the fourth quadrant
So, sine must be negative in the fourth quadrant
Using identity 
to find sine value
Answer:
401
Step-by-step explanation:
1. Approach
To solve this problem, one first has to think about the given figure in a certain way. In the figure, one can see that it is a circle attached on either side of a rectangle. To find the perimeter of the figure, one has to find the circumference of the circle and then add two sides of the rectangle to the answer
2. Circumference of the circle
The formula to find the circumference of a circle is;
(pi) or 
(pi)
~ diameter times the value (pi)
Normally to find the circumference of a semicircle, one would have to divide this formula by 2, but since in this case, one has to add two congruent semicircles, so therefore, the effect of dividing the equation by two, only to multiply by two again cancels, and hence, there is no need to divide by 2.
Substitute in the values;
(78)(pi)
~ 245
3. Find the perimeter of the entire object
Now, one has to add the two additional sides of the figure, to the circumferences of the semicircles to get the final answer;
78 + 78 + 245
= 401
Equilateral: all sides are the same length
isosceles: two sides are the same length
obtuse: there is 1 obtuse angle
Answer:
Step-by-step explanation:
Given that points scored is the dependent variable Y and Number of people attending the game is the independent variable is independent variable x
The correlation coefficient, slope and intercept are calculated as shown below:
x y
378 54
350 57
320 59
478 80
451 82
250 75
489 73
451 53
410 67
215 78
113 67
250 56
450 85
489 101
472 99
Mean 371.0666667 72.4
std dev 117.5138087 15.42632259
covariance 667.5733333
r 0.394558035
Slope 3.005642934
Intercept 153.4581182
y = 3.006x+153.46 is the regression line.
Corre = 0.3945 (weak positive)
