SPM 2020 Add Maths Paper 1, Question 4Quadratic Functions

Solved on video in English and Bahasa Melayu · 6 marks · Form 4, Quadratic Functions · 3:30 video

The question

(a)

The quadratic equation x(px + q) = -5, where p and q are constants, has two equal roots. Express the quadratic equation in general form.

[3 marks]

(b)

Express p in terms of q.

[3 marks]

Step 1

Expand the left side: x(px + q) = px² + qx.

2 more steps, each with the reason for it, in the full solution

Final answer

px² + qx + 5 = 0

Where students lose marks

Watch out: −5 becomes +5 when it crosses the equals sign. Writing px² + qx − 5 = 0 is a sign slip.

4 more steps, each with the reason for it, in the full solution

Final answer

p = q²/20

Where students lose marks

Watch out: equal roots need b² − 4ac = 0, not > 0. Using > 0 gives p < q²/20 and loses marks.

Watch every step of this question solved on video (3:30), with the reason behind each step and a box that checks your own answer.

No card. Every past-year question on video, in English and BM.