Question 70·Easy·Linear Equations in Two Variables
Which table gives three values of and their corresponding values of for the given equation?
For questions asking which table matches a linear equation, quickly plug in the -values from the tables into the equation and compute the corresponding -values. Start with easy values like to find the -intercept, then check one or two more -values; eliminate any table where the -values do not match your calculations, focusing on both the starting value and how changes as increases.
Hints
Start with
If , the equation becomes . What is ? Then look for the table(s) that have that same -value when .
Check how changes when increases by 1
Because the equation is , each time increases by 1, should change by . Look down the -column in each table and see which one shows that change.
Verify with substitution
Take and and plug them into . Then compare the -values you get to the -values in each table for those -values.
Desmos Guide
Graph the equation
In Desmos, type the equation on a new line so the line appears on the graph.
Create a table of values
Click the gear or plus icon next to the equation and choose the option to create a table (or add a separate table and label the columns and ).
Enter the given -values and read the -values
In the -column of the table, enter 0, 1, and 2. Desmos will automatically fill in the corresponding -values from the equation. Compare those three pairs with the answer choices to see which table matches.
Step-by-step Explanation
Understand what the equation tells you
The equation means: to get , multiply by and then add 5. So for any -value in a table, you can compute the matching -value with this rule.
Find when
Substitute into the equation : . So when , must be 5. Eliminate any table whose first row does not have paired with .
Find when
Now substitute : . So when , must be 3. Check which remaining table(s) have paired with .
Find when and match the table
Finally, substitute : . So the correct three pairs are , , and , which matches the table
| x | y |
|---|---|
| 0 | 5 |
| 1 | 3 |
| 2 | 1 |
This is answer choice D.