If f(x) is a function and f(1) = 5, then which of the following could not be true?
f(1) = 1 
f(2) = 1
f(5) = 5

Solution:

Given f(x) is a function and f(1) = 5

A function is an expression, rule, or law that defines a relationship between one variable (the independent variable) and another variable (the dependent variable).

A function can allow many-to-one mapping but doesn’t allow one-to-many mapping.

f(2) can give the value of 1 and f(5) can give the value of 5.

Hence, f(1) = 1 can not be true as we already have f(1) = 5

If f(x) is a function and f(1) = 5, then which of the following could not be true?

Summary:

If f(x) is a function and f(1) = 5, then f(1) = 1 could not be true.