Question 187·Easy·Nonlinear Functions
Which table gives three values of and their corresponding values of for the given function ?
When a question asks which table matches a given function, ignore the choices at first and quickly compute the outputs the function gives for the listed -values, being careful with order of operations (exponent first, then addition or subtraction). Once you have the correct outputs, scan the tables for an exact match on all the corresponding -values; if even one output is off, eliminate that option and move on. This direct substitution approach is fast and avoids getting distracted by patterns in the answer choices.
Hints
Use the definition of the function
tells you how to get the output from any input . What should you do with each -value from the table?
Start with
Substitute into . Remember that equals . What does that make ?
Repeat for and
Now plug in and then into . Be careful to calculate first and then add .
Compare your results to the options
Once you know , , and , look for the table whose row matches all three of your computed values.
Desmos Guide
Enter the function into Desmos
Type y = 2^x + 1 (or g(x) = 2^x + 1) into a new expression line so Desmos knows the function.
Evaluate the function at the given x-values
Either add a table in Desmos with -values , , and next to the equation, or type separate lines 2^0+1, 2^1+1, and 2^3+1. Read off the three outputs and then choose the table option whose row matches all three values.
Step-by-step Explanation
Understand what the function means
The function is . This means: for any input ,
- First compute (2 raised to the power),
- Then add to that result.
We need to do this for , , and .
Compute
Substitute into :
We know , so:
So when , .
Compute
Now substitute :
We know , so:
So when , .
Compute and match the table
Finally, substitute :
We know , so:
So the correct table must show values , , and for , , and , respectively. The only table that does this is:
| 0 | 1 | 3 | |
|---|---|---|---|
| 2 | 3 | 9 |