Question 73·Easy·Linear Inequalities in One or Two Variables
Which of the following ordered pairs satisfies both inequalities below?
I.
II.
III.
IV.
For questions asking which points satisfy one or more inequalities, the fastest approach is to plug each given point directly into the inequalities rather than solving them algebraically. For each ordered pair, compute the left-hand side of each inequality and quickly check if it meets the condition (remembering the difference between , , , and ). Discard any point as soon as it fails one inequality, and at the end, match the remaining valid point(s) to the answer choice.
Hints
Use substitution
For each ordered pair, substitute the x-value and y-value into the expressions and . Then check whether the resulting numbers make each inequality true.
Be careful with inequality types
Remember that allows the left side to be equal to or less than the right side, but requires the left side to be strictly greater than the right side (equal is not enough).
Stop as soon as a point fails
If an ordered pair fails either inequality, you can immediately discard it and move to the next one—you do not need to check anything else for that point.
Desmos Guide
Graph the inequalities
In Desmos, type the inequalities exactly as given on separate lines:
2x + y <= 5x - y > -1Desmos will shade the solution region for each inequality; the overlapping shaded region represents points that satisfy both inequalities.
Plot the candidate points
On new lines, enter each point in curly braces to plot it: {0,5}, {2,0}, {1,3}, and {3,2}. Desmos will display each as a dot on the graph.
Identify which point lies in the overlap
Look for the dot that lies inside the region where the two shadings overlap (the common solution area). The ordered pair corresponding to that dot is the one that satisfies both inequalities; then choose the answer option that lists only that pair.
Step-by-step Explanation
Understand what it means to satisfy both inequalities
We need an ordered pair that makes both statements true:
- ("less than or equal to 5")
- ("strictly greater than ")
Any pair that fails either one of these inequalities cannot be an answer.
Check point I: (0, 5)
Substitute , into each inequality.
- First inequality: , and is true.
- Second inequality: , and is false.
So does not satisfy both inequalities.
Check point II: (2, 0)
Substitute , .
- First inequality: , and is true.
- Second inequality: , and is also true.
So satisfies both inequalities.
Check points III and IV to confirm they do not work
Now test the remaining points.
Point III:
- First inequality: , and is true.
- Second inequality: , and is false. So does not satisfy both inequalities.
Point IV:
- First inequality: , and is false. Since it already fails the first inequality, cannot be a solution.
Only one of the four points works.
Match the working point to the answer choice
We found that only point II, , satisfies both inequalities. The answer choice that lists only point II is "II only," which is choice D.