A linear relationship (or linear association) is a statistical term used to describe the directly proportional relationship between a variable and a constant.

Example Find the equation of the line that goes through the points (−1, 3) and (3, 11). Sketch the two points and join them with a straight line.

Revise how to recognise and determine the equation of a quadratic function from its graph. BBC Bitesize Scotland revision for SQA National 5 Maths.

So x + 4 is an expression describing a straight line, but (x + 4)² is a curve ... Loh is right that this will smooth students’s understanding of how quadratic equations work and how they fit into math ...