Find the gradient of y = 2x + 1
- Compare with y = mx + c.
- The number multiplying x is 2.
- So the gradient is 2.
Answer: Gradient = 2
𝑥 Algebra
Straight line graphs
Understand coordinates, gradients and y = mx + c using a graph.
Global XP
Level 10 / 100 XP
1. Explanation
Key idea
- A straight line graph can be written as y = mx + c.
- m is the gradient: how steep the line is.
- c is the y-intercept: where the line crosses the y-axis.
Real-life examples
- Taxi fares with a starting charge and a cost per mile.
- Saving the same amount of money each week.
2. Visual
Graph of y = 2x + 1
3. Help guide
How to tackle Straight line graphs
- Learn the rule: Straight line graphs often use y = mx + c.
- Worked model: Compare with y = mx + c. Read m as gradient. Read c as y-intercept.
- Try the interactive question without looking at the answer first.
- Use the flashcards to test the rule, the method and a common check.
4. Worked examples
Step-by-step working
5. Interactive questions
Try it yourself
In y = 3x + 5, what is the y-intercept?
6. Flashcards
Master quick recall
Flip each card, then choose whether you know it or need more practice.
0 mastered
FrontIn y = mx + c, what does m mean?
Backm is the gradient.
FrontIn y = mx + c, what does c mean?
Backc is the y-intercept.
FrontRule for Straight line graphs
BackStraight line graphs often use y = mx + c.
7. Finish
Complete this topic
When you have read the examples, tried the question and reviewed flashcards, claim your topic completion XP.