You have the following expression:

To verify the identity, you have that the left side of the equation becomes:
(1 + cosx)(1 - cosx) = (1 - cos^2 x)
because of the product of an expression by its conjugate result in a difference of squares. Or simplfy by expanding the factors and simplying.
Next, you have:
1 - cos^2 x = sin^2 x
because the Pythagorean identity.
Then, the identity is verified.
1/4 mile per minute is the average speed.
Answer:
$7
Step-by-step explanation:
To solve this one we will subtract how much he spends from what he has. At the start he had 19 and then spent 8 meaning he now has 8 less than when we started so 19-8 is 11. He now as 11 dollars, then he spend another 4 meaning we have to subtract another 4 dollars. 11-4 is 7. So he as 7 dollars left at the end.
I hope this helps and please don't hesitate to ask if there is anything still unclear!
Okay so the circle on the line plot, if it is empty In the middle it is > or < if it is solid it is ≤ ≥. In this case it not solid so it will be > or < . The plot is at -1 1/2 and is going positive. So it would be a > -1 1/2