Answer:
it is a function
Step-by-step explanation:
the input is not repeated
Answer:
x∈{-7√2, 7√2}
Step-by-step explanation:

Answer: No it's not
Step-by-step explanation:
1/3 x 6/1 = 6/3
6/3 = 2
Answer: f(4) = 21
Step-by-step explanation:
2(4)^2-11
4^2 = 16
2(16)-11
Multiply 2 and 16
32 - 11
Subtract
21