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0580/13 May/Jun 2021, Question 21: The Equation y = mx + c

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

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The question, in short

Use the given graph of straight line L to determine its equation in the form y = mx + c, then find a second line's equation from given conditions.

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

Part (a) · 2 marks

From the graph of line L, find its gradient and intercept to write the equation as y = mx + c.

  1. 1Line L crosses the y-axis at (0, 2) and the x-axis at (4, 0)
  2. 2Gradient = (0 − 2)/(4 − 0) = −1/2
  3. 3y = −1/2 x + 2

Answer−0.5x + 2 or −1/2 x + 2

Part (b) · 1 mark

Find the equation of the line parallel to y = 3x − 5 that passes through (0, 17).

  1. 1Parallel lines have the same gradient, m = 3
  2. 2The line passes through (0, 17), so c = 17
  3. 3y = 3x + 17

Answery = 3x + 17

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Also searched as: 0580/13/M/J/21 · 0580_s21_qp_13 · 0580 s21 13 · question 21.
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