What is the boundary line of \(x\leq 5\)?

Correct answer: \(x=5\)

To find the boundary line of \(x\leq 5\), replace the inequality sign with an equality sign. Hence, the boundary line is \(x=5\), which is a vertical line. All points satisfying \(x\leq 5\) lie on this line or to its left. \(y=5\) is a horizontal line, so it is not correct. Exam tip: Replace \(\leq\) or \(\geq\) with \(=\) to obtain the boundary line.