ECZ 2015 · O-Level Paper 2 · Question 2 — Quadratic Equations

Question from ECZ 2015 · O-Level Paper 2 · Question 2

(a) Solve the equation 2y2 + 6y - 1 = 0, giving your answers correct to 2 decimal places.[5]

Verified working — step 1

a = 2, b = 6, c = -1.

(b) Given that matrix Q = a23-2,

(b(i)) write an expression in terms of a for the determinant of Q,[1]

Verified working — step 1

Q = a23-2.

(b(ii)) find the value of a, given that the determinant of Q is 2,[2]

Verified working — step 1

Set the determinant equal to 2.

(b(iii)) write Q-1.[1]

Verified working — step 1

With a = -4, Q = -423-2 and det Q = 2.

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Original examination question © Examinations Council of Zambia. Worked solution and commentary © G12 Titan — not to be reproduced without permission.

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