Maths · KS3 Y8 · Algebra

Horizontal & vertical lines

Horizontal & vertical linesFree6:52Heddy Score 3 of 7, below the standard

What you need to know

  • In y = mx + c, m is the gradient and c is the y-intercept, where the line crosses the y-axis.
  • Gradient is the change in y divided by the change in x between two points on the line.
  • Keep each point's coordinates together when working out the gradient.
  • Horizontal lines have a gradient of zero and vertical lines have an undefined gradient.
  • A line can be drawn from one point and its gradient by moving up and across.

In this clip

0:00–5:46Finding the equation of a line
Also coversHorizontal & vertical lines
Heddy Score3/7, Below the standard
See the seven stars
  • Trusted source · passed. The creator's own upload, live and playable here.
  • On the map · not judged yet. A teacher watched it: it mainly teaches this map topic.
  • Spec-true · not judged yet. Accurate, and right for the current UK specification.
  • Focused · passed. One idea, short enough to watch in one go.
  • Accessible · passed. Good captions, clear sound and pictures.
  • Safe for children · not judged yet. Right for 11 to 16 year olds, with no sales pitch.
  • Proven · not judged yet. Earned from our students: they learn from it, find it helpful and watch it to the end.
★ passed · ☆ pending · ✕ failed
Our students

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Our own students' answers. These are what move ★7 Proven.
On YouTube

1.01M views · 15K likes · Professor Dave Explains 4.49M subscribers

As reported by YouTube on 2026-11-02. Not part of the Heddy Score.
How the Heddy Score works

Why we picked it

Explains what the gradient and intercept mean and how to calculate gradient from two points.

Professor Dave Explains on YouTubechecked 2026-10-22

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