Quick questions on Linear inequalities explained: O-Level E-Maths

The four signs are less than $<$, greater than $>$, less than or equal to $\le$, and greater than or equal to $\ge$. A strict sign ($<$ or $>$) excludes the boundary value; an inclusive sign ($\le$ or $\ge$) includes it.

Solve an inequality almost exactly as you solve an equation: add, subtract, expand and collect terms freely. The one exception is that multiplying or dividing both sides by a negative number reverses the direction of the inequality. So from $-3x < 12$ you divide by $-3$ to get $x > -4$, with the sign flipped.

Draw the solution as a shaded region on a number line. Use an open (hollow) circle at a boundary that is excluded by a strict inequality, and a closed (filled) circle at a boundary included by an inclusive inequality, then shade in the direction of the solution.

A strict inequality needs an open circle; an inclusive one needs a filled circle.

Solve $2x - 5 < 9$. [2 marks]

Solve $-4x \ge 20$. [2 marks]

List the integers satisfying $-2 \le x < 3$. [2 marks]