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If g(x) is the inverse of f(x), what is the value of f(g(2)?

If g(x) is the inverse of f(x), what is the value of f(g(2)?-example-1
User Thewads
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1 Answer

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Answer: C) 2

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Step-by-step explanation:

g(x) is the inverse of f(x), which tells us that g undoes everything f(x) does.

If we input x = -6 then f(x) outputs 1

g(x) then reverses this to say that g(1) = -6. The inputs and outputs swap roles.

Moving to row 2, we see that f(-3) = 2 which reverses to g(2) = -3

We'll replace the g(2) with -3 to go from

f( g(2) )

to

f( -3 )

-3 isn't the answer, but I wanted to put it in bold to show how the replacement is happening.

From the table, we see that f(-3) = 2 which is the final answer

In other words, f(g(2)) = 2

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Side note:

We can say that f(g(x)) = x for any number x in the domain of g(x).

As another example, g(3) = 5 and f(g(3)) = f(5) = 3.

The same works the other way around meaning that g(f(x)) = x.

User D Durham
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