19^2 + x^2 = 21^2
19^2 = 361
21^2= 441
361 + x^2 = 441
x^2 = 441-361 = 80
x = sqrt(80) = 8.944 round to nearest tenth = 8.9
For each answer, we can plug in the given points:
A) is technically the same as B), but B) expresses correct function notation.
B) 5 = 5(1)
⇒ 5 = 5
25 = 5(2) ⇒ 25 ≠ 10
B) is incorrect.
C) I'm not sure what you mean y=5^5=x, but I'm going to use

because it's close to what you wrote:

The function

works for the points given.
D) 5 = 1 + 5 ⇒ 5 ≠ 6
D) is not correct.
Please check your functions; I'm not sure that C) is a function. In any case, the answer is C) because all the other answers are wrong.
Answer:
The answer to your question is the third option
Step-by-step explanation:
To know if two lines are parallel we must get their slopes if the slopes are equal, the lines are parallel.
Data
A (2,2)
B (3,6)
C(0,5)
D(1,9)
Formula
slope = 
Process
1.- Calculate the slope of line 1
slope 1 = 
slope 1 = 
slope 1 = 4
2.- Calculate slope 2
slope 2 = 
slope 2 = 
slope 2 = 4
3.- Compare the slope
slope 1 = 4 and slope 2 = 4, both slope are equals, then the lines are parallel.
If you calculate 20^10/4^42 then you will find out it equals25
Answer:
C (0,1)
D (0,0)
E (0,-1)
G (0,5)
Step-by-step explanation:
The x coordinate has to be a zero so that the point could be on the Y-axis