Chapter 4 Quadratic Functions and Factoring - 4.2 Graph Quadratic Functions in Vertex or Intercept Form - 4.2 Exercises - Mixed Review - Page 251: 70

$=\begin{bmatrix} 84& 16&108\\ 48 &12 & 56 \end{bmatrix}$

Given: $CD=\begin{bmatrix} -1 & 4\\ -2 &3 \end{bmatrix}\begin{bmatrix} 3 & 0 & -1\\ 6 & 1 & 4 \end{bmatrix}$ $=\begin{bmatrix} 21 & 4&17\\ 12 &3 & 14 \end{bmatrix}$ so $4\begin{bmatrix} 21 & 4&17\\ 12 &3 & 14 \end{bmatrix}=\begin{bmatrix} 84& 16&108\\ 48 &12 & 56 \end{bmatrix}$