y = mx + c

MathematicsAQAEdexcelGCSEUnit: Graphs
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The basics

Building the Perfect Equation

🏗️ Building the Perfect Equation

Think of y = mx + c as a recipe for building any straight line! Just like a building needs a foundation (c) and a direction (m), every straight line needs these two ingredients. The equation y = mx + c is like having the blueprint that tells you exactly how to construct any straight line.

This format is so powerful that it's used everywhere - from calculating phone bills to predicting profit in businesses!

Exam tip

Earn the mark scheme marks

💡 Exam Tips for y = mx + c

  • Check signs carefully: Is it +c or -c? Is m positive or negative?
  • Read intercepts accurately: Use the grid lines to find exact values
  • Show gradient calculations: Always write out the rise/run fraction
  • Verify your answer: Substitute a point from the line into your equation
  • Label your answer clearly: Write "The equation is y = ..."
  • Use fractions when necessary: Don't always convert to decimals

Now try it yourself

Quiz · Question 1 of 10

For the line y = 3x – 2, what is the gradient?

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