Recognise Horizontal and Vertical Lines Using x and y Coordinates

When you are learning to recognise and sketch equations of lines, a lot of emphasis is put on finding equations of diagonal lines (so called y = mx + c lines).

The thing that is commonly skated over is recognising and drawing lines of the form x = a and y = b.

x = a and y = b

To put it simply, these are horizontal and vertical lines.

Lines with the equation x = a are vertical lines that go through the x-axis at the point a.

All the points on this line have an x coordinate of a.

Lines with the equation y = b are horizontal lines that go through the y-axis at point b.

All the points on this line have a y coordinate of b.

Let's have a go at some questions.