What you’ll learn
Students will interpret, construct, and verify number-line graphs for strict inequalities of the form x > c or x < c, using an open endpoint at c and the correct ray direction.
Key idea
A strict comparison requires an open endpoint and a ray toward the allowed values.
Worked example
Enter the exact value or ordered values in the format requested below.
Read the number-line graph: labeled ticks -15, -14, -13, -12, -11; OPEN endpoint at -13, shaded ray LEFT. Enter its strict inequality using x.
- The boundary is -13; strict < excludes it, requiring an open endpoint.
- The allowed values lie to the left, so the graph is open@-13;left.
Answer: x<-13
Quick Check
Identify whether a proposed strict graph has the wrong endpoint type, direction, or both, then repair it.
For x>0, a student draws a OPEN endpoint at 0 with a ray LEFT. Classify the wrong features and supply the corrected graph.