Cogito
Algebra 1 · Chapter 2 · Lesson 5
Inequalities in Two Variables
A whole region of the plane, not a line.
11 problems · about 23 minutes · A-REI.D.12
Figure — use these to answer the problems
Warm Up
Straightforward practice. Get the method working first.
4 problemsDoes (0, 0) satisfy y < x − 3? 1 for yes, 0 for no.
Answery > x + 2. Is the boundary dashed? 1 for yes, 0 for no.
AnswerDoes (0, 0) satisfy y > x + 2? 1 for yes, 0 for no.
AnswerDoes (0, 5) satisfy y > x + 2? 1 for yes, 0 for no.
Answer
Build It Up
The same ideas with more to keep track of.
3 problemsy ≥ 2x. Is the boundary solid? 1 for yes, 0 for no.
AnswerOrder the steps for graphing a linear inequality.
Write 1 to 4 in the boxes to put these in order.
- Graph the boundary line
- Make it solid or dashed
- Test a point off the line
- Shade the side that works
Does (2, 1) satisfy y < x? 1 for yes, 0 for no.
Answer
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
4 problemsCan the origin be used as a test point for y < x? 1 for yes, 0 for no.
AnswerHow many points satisfy a linear inequality in two variables? Use 99 for infinitely many.
AnswerTesting a Point
Does (0, 0) satisfy y < 2x + 1? 1 for yes, 0 for no.
AnswerThe Line Style
For y ≤ 3x, is the boundary solid? 1 for yes, 0 for no.
Answer