CAPE Pure Mathematics Unit 2 · May/June 2017 · Paper 2 · Question 5(c)(iii)

Given the matrices A = \begin{pmatrix} 1 & -1 & 1 \\ 1 & -2 & 4 \\ 1 & 3 & 9 \end{pmatrix}, B = \begin{pmatrix} 30 & -12 & 2 \\ 5 & -8 & 3 \\ -5 & 4 & 1 \end{pmatrix}.

Hence, or otherwise, solve the system of linear equations given by: \begin{aligned} x - y + z &= 1 \\ x - 2y + 4z &= 5 \\ x + 3y + 9z &= 25 \end{aligned}