The matrix A is (4 5 / 3 2) and the matrix B is (4 2 / 1 3).

Mark scheme

Marking points from the official mark scheme (May/June 2016). The mark or mark type is shown in brackets.

1. [M1] (12 15 / 9 6) + (4 2 / 1 3) soi if no method shown, may be implied by their answer with at least 2 correct elements
2. [A1] (16 17 / 10 9)
3. [B1] detA = 4 x 2 - 3 x 5 = -7 or detB = 4 x 3 - 2 x 1 = 10 allow for e.g. (4 x 2 - 3 x 5) x (4 x 3 - 2 x 1) = -70 or detA = 8 - 15 = -7 or detB = 12 - 2 = 10
4. [B2] AB = (21 23 / 14 12) or B1 for two elements correct
5. [B1] det(AB) = 21 x 12 – 23 x 14 = -70 allow for det(AB) = 252 – 322 = -70
6. [B2] 1/(their det AB) x their (12 -23 / -14 21) isw correct or correct FT; FT their AB and their non-zero det AB; their AB must be an attempt at a matrix product e.g. (16 10 / 3 6) B1 for 1/(their det AB) x (their (12 -23 / -14 21)) or for k x their (12 -23 / -14 21)