Straight-Line Graphs
Every straight line has a steepness (m) and a starting point (c).
y = mx + cGradienty-interceptGradient from two points
📖 Learn
y = mx + c
m is the gradient (steepness). c is where the line crosses the y-axis.
Gradient
Change in y ÷ change in x. Uphill left-to-right = positive.
Parallel
Parallel lines have the same gradient.
Worked example
Gradient between (1, 3) and (4, 12)
- 1Change in y: 12 − 3 = 9
- 2Change in x: 4 − 1 = 3
- 39 ÷ 3 = 3 ✅
⭐ Practise
π
Ask Professor Pi
Type a question or say where you're stuck. You'll get hints, not just answers!
AI-powered tutor — it can make mistakes, so check with your teacher if unsure.