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0580/13 Oct/Nov 2023, Question 17: Finding the Equation From a Graph

Cambridge IGCSE Mathematics 0580 · Paper 13 (Core) · Calculator · 3 marks

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The question, in short

A straight line L is shown on a grid with x from −2 to 4 and y from −1 to 4. Work out its equation as y = mx + c, then add a perpendicular line to the grid.

Summarised in our own words. Use the official paper for the exact wording and the diagram.

Part (a) · 2 marks

Work out the gradient and intercept of the drawn line L and state its equation as y = mx + c.

  1. 1L crosses the y-axis at (0, 1), so c = 1
  2. 2L passes through (3, 2): gradient = (2 − 1)/(3 − 0) = 1/3
  3. 3y = 1/3 x + 1

Answery = 1/3 x + 1

Part (b) · 1 mark

Add a second straight line to the grid that meets line L at right angles.

  1. 1Perpendicular gradient = −1 ÷ 1/3 = −3
  2. 2Rule a straight line with gradient −3, e.g. through (0, 1) and (1, −2)

AnswerAny ruled perpendicular line

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Also searched as: 0580/13/O/N/23 · 0580_w23_qp_13 · 0580 w23 13 · question 17.
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