If ƒ (a) = K, then which of the following must be true?

Answer choices:

1. ƒ (K) = a

2. ƒ - 1 (K) = a

3. ƒ - 1 (a) = K

Number 2 is the correct answer

F (a) = k

means

when you input a, in f (x), you get k

lets see

1., this is false, unless f (x) = x which is not always true

2. this is the inverse, this is the sme function but input and output are switched

f (a) = k turns to f⁻¹ (k) = a

true

3. this is true only if f (x) = x

2 is the right answer