ECZ 2024 · GCE Paper 2 · Question 4 — Matrices

Question from ECZ 2024 · GCE Paper 2 · Question 4

(a) Solve the equation 7 - 2x2 = x, giving your answers correct to 2 decimal places.[5]

Verified working — step 1

Rearrange to standard form: 2x2 + x - 7 = 0, so a = 2, b = 1, c = -7.

(b) Given that matrix B = 4x-1-3x,

(b(i)) find the value of x for which the determinant of B is 22,[2]

Verified working — step 1

det B = (4)(-3x) - (x)(-1) = -12x + x = -11x

(b(ii)) hence, find the inverse of B.[2]

Verified working — step 1

With x = -2: B = 4-2-16 and det B = 22.

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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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