Completing the square
Edexcel GCSE Maths revision on Completing the square. Aligned to the Pearson Edexcel GCSE Mathematics 1MA1 specification. This bank has 16 practice questions on this topic.
Sample questions (3 of 16)
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Question 1
What is the result of completing the square for the expression x squared plus 6x plus 5?
- A) (x + 3)^2 - 4
- B) (x + 3)^2 - 5
- C) (x + 6)^2 - 4
- D) (x + 6)^2 - 5
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Answer: (x + 3)^2 - 4
To complete the square for x^2 + 6x + 5, we take half of 6, which is 3, to get (x + 3)^2. We then subtract 3^2 (which is 9) and add the original 5, resulting in -4.
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Question 2
Which expression represents the completed square form of x squared minus 8x plus 10?
- A) (x - 4)^2 - 6
- B) (x - 4)^2 - 8
- C) (x - 8)^2 - 6
- D) (x - 8)^2 - 8
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Answer: (x - 4)^2 - 6
Completing the square for x^2 - 8x + 10 gives (x - 4)^2 - 16 + 10. Simplifying this results in (x - 4)^2 - 6.
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Question 3
What is the value of q when the expression x squared plus 10x plus 3 is written in the form (x + p) squared plus q?
Show answer
Answer: -22
Completing the square gives (x + 5)^2 - 25 + 3. Therefore, q is equal to -22.
Want to test yourself on the remaining cards for this topic?
13 more questions on Completing the square — plus mistakes tracking and spaced repetition across the whole Maths spec.