Its A. B. and C.............
Answer:
y = 90
Step-by-step explanation:
Since, e || f and a || b
Therefore, quadrilateral so formed is a rectangle.
Each angle of a rectangle is right angle.

Hey there!
The answer to your question is 
Given:

First, we distribute the negative sign to both terms (
) This would make the
negative and the
positive, so we have:

Add them together and we get:

Have a nice day!
1, 3, 5 are functions because they pass the vertical line test
3x=4y
x+y=21
x = 21-y
3(21-y)=4y
63-3y=4y
63=7y
y=9
x+y=21
x+9=21
x=12
answer is (12, 9)