Graphing Inequalities (Edexcel IGCSE Maths A (Modular))

True.

A solid line is used when drawing the line for the inequality .

Solid lines are used when the inequality includes an equals, ≤ or ≥.

The side to the left of the line (including the line itself) satisfies the inequality .

False.

The region below the line does not satisfy the inequality .

The region above the line satisfies the inequality.

To use the point to determine which side of the line satisfies the inequality :

• Substitute and into .

• If the answer is greater than 12 then the side of the line containing satisfies the inequality.

• If the answer is less than 12 then the side of the line which does not contain satisfies the inequality.

To identify the inequalities needed to define a region from a graph:

• Identify the equation of each line.

• Substitute the coordinates of a point within the region into each equation.

  • If the answer is less than the given value in the equation, then it satisfies the inequality (if the line is dotted) or (if the line is solid)

  • If the answer is greater than the given value in the equation, then it satisfies the inequality (if the line is dotted) or (if the line is solid)