A
rational number is any number that can be written as the
ratio between two other numbers i.e. in the form

Part A:
An easy choice that makes sense is 7.8, right in the middle. To prove that it's rational we need to write it as a ratio. In this case we have

Part B:
We need a number that can't be written as a ratio (because it neither terminates nor repeats). Some common ones are

,

,

and

so it makes sense to try and use those to build our number. In this case

works nicely.
Remark
That was well worth doing. Desmos gave you the answer to the graph. Unfortunately I can only give you the correct graph. You will have to figure out from the choices which one is the correct answer -- or edit it so I can see what the rest of the question is.
Graph
The red one is f(x) is x + 3 {x <= -2}
The blue one is f(x) is x^2 - 1 {-2 <x <1} Notice the gap at 2. It is not continuous
The green one is f(x) is log_2(-x + 3) {1 <=x < 3} and there is a gap between the blue and green one.
The answer is 97, because when you add up 42 and 55 you get 97. Then you subtract that by 180 because a triangles angles add up to 180. 180-97=83. Z=83. Z and y are supplementary to eachother, so therefore 180-83= 97. Supplementary means they add up to 180.
B. 42 degrees
Angle ABC is an inscribed angle so u have to divide Arc AC by 2 to find angle ABC.
84degrees divided by 2 is 42 degrees.
F (x)= x+12 is the inverse of the function