4MA1/2H Jan 2022, Question 21: Solving Equations by Graphical Methods
Pearson Edexcel International GCSE Mathematics A 4MA1 · Paper 2H (Higher) · Calculator · 5 marks
اقرأ هذا الحل مشروحاً بالعربي ←
The question, in short
Using the given graph of y = 2x² − 4x − 1, estimate roots of two related equations to one decimal place, drawing a line where needed.
Summarised in our own words. Use the official paper for the exact wording and the diagram.
Part (a) · 2 marks
Use the curve to estimate where 2x² − 4x − 1 = 0, giving solutions to one decimal place.
- 1Locate where the graph crosses the x-axis
- 2Read off the x-values at the points of intersection with the x-axis
- 3−0.2 and 2.2
Answer−0.2 and 2.2
Part (b) · 3 marks
Draw a suitable straight line on the grid to estimate solutions of x² − x − 1 = 0 to one decimal place, showing working.
- 1Multiply x² − x − 1 = 0 by 2: 2x² − 2x − 2 = 0
- 2Rearrange to match the curve: 2x² − 4x − 1 = −2x + 1
- 3Draw the line y = −2x + 1 through (−1, 3) and (2, −3)
- 4Read where the line crosses the curve: −0.6 and 1.6
Answer−0.6 and 1.6
Stuck on a step? Read the free lesson: Solving Equations by Graphical Methods
Practise more solving equations by graphical methods questions
Real 4MA1 past-paper questions, marked on your working like the exam, with a worked solution for every part.
Practise free on LemmaraMore past-paper questions on solving equations by graphical methods
Also searched as: 4MA1 2H January 2022 · 4MA1/2H · 4ma1 jan22 2h · question 21.
Lemmara is an independent study tool, not affiliated with or endorsed by Pearson Edexcel. The worked solutions are Lemmara’s own.