On December 20, 2023, Brent will stop offering office hours.

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## Comment on

Functions f and g## Thank you very much for the

## That's a common trick the

That's a common trick the GMAT test-takers like to pull. We THINK the goal is to find the value of k, but we ACTUALLY need to find the value of f(k+1)

## Hi Brent, as you mentioned we

## Be careful. The value of k+1

Be careful. The value of k+1 is not the same as the value of f(k+1).

Once we learn that k = -5, our goal is to find the value of f(k+1)

So, when we replace k with -5, we get: f(k + 1) = f((-5) + 1) = f(-4)

So, we still need to find the value of f(-4)

Since f(x) = 3x + 1, we know that f(-4) = 3(-4) + 1, which equals 11.

Does that help?

## Thanks Brent for great

## That's correct.

That's correct.

## Hi. I want more practice with

## We have links to functions

We have links to functions questions in the Reinforcement Activities box here: https://www.gmatprepnow.com/module/gmat-algebra-and-equation-solving/vid...

## Hi Brent,

Just a quick question. Why can't I solve for k by equating f(k+1) = g[(k+1)/2] and then solve it? Theoretically, it should be the same right?

## That approach will kind of

That approach will kind of work, but you will be forced to perform some VERY TRICKY mental maneuvering during the solution.

Try it and you'll see.

Cheers,

Brent