Scenario: A kid initially has 7.6 dollars and is given 0.2 dollars every weekend. The slope here is the 0.2. This is the value or increment in which the money is increasing. The y-intercept is the value we obtain from the equation when we set x to zero. Similarly speaking, this is the original value which is 7.6.
Answer:

Step-by-step explanation:
Lets solve the first half.

Second one:

Now compare.....Not the same right??
So your answer is: 
Hope this helps :)
Answer:
12/30
Step-by-step explanation:
So we know that the denominator-numerator=18
And we also know that it's equal to 4/10 or 2/5.
Soooooooooooooo the most easiest is just to trial and error: 12/30
But I don't really know the more complex formula...
Answer:
20/29
Step-by-step explanation:
sin θ = 21/29
Use Pythagorean identity:
sin² θ + cos² θ = 1
(21/29)² + cos² θ = 1
441/841 + cos² θ = 1
cos² θ = 400/841
cos θ = ±20/29
Since 0° < θ < 90°, cos θ > 0. So cos θ = 20/29.
Attached the solution and work.