(A) (5, 11), (-8, 2), (0, 7), (-5, 11)
:- Yes, this is a function. Two or more inputs can have the same output but no two outputs can have a same input. Here, domain 5 & -5 bears same output 11. Thus, it's a function.
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(B) (5, 11), (-8, 2), (0, 7), (0, -5)
:- Not a function. Because here, an input '0' have two different outputs 7 and -5. And, we know for a function no two outputs can have a same input.
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(C) (0, 11), (-8, 2), (0, 7), (-8, -5)
:- Not a function. Because here, an input '0' have two different outputs 11 and 7. Similarly an input '-8' have two different outputs 2 and -5. And, we know for a function no two outputs can have a same input.
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(D) (11, 5), (2, -8), (7, 0), (11, -5)
:- Not a function. Because here, an input '11' have two different outputs 5 and -5. And, we know for a function no two outputs can have a same input.
