Year 9 Linear Relationships

Linear relationship

A set of ordered pairs that give a straight line

Horizontal line: y = b

Parallel to the x-axis, the y-coordinate is the same for every point on the line.

Vertical line: x = a

Parallel to the y-axis, the x-coordinate is the same for every point on the line.

The origin.

The point (0, 0) where the x-axis and y-axis intersect at right angles.

The Cartesian plane (or number plane)

consists of two axes that divide the number plane into four quadrants.

The gradient

is a measure of its steepness or slope.

y = mx + b

is the gradient-intercept form of a straight line equation. m is the gradient b is the y intercept

The x-axis

is the horizontal axis.

The y-axis

is the vertical axis.

The midpoint (M) of a line segment

the halfway point between the two endpoints.

The x-intercept

the x-value of the point where the line cuts (intersects) the x-axis.

The y-intercept

the y-value of the point where the line cuts (intersects) the y-axis.