Equations as Matrices Practice

1. Write the following system of equations as an augmented matrix.

   Represent each row and column in the order in which the variables and equations appear below.
   

   $\begin{aligned}8x-5y=19\\6x+11y=29\end{aligned}$

2. $\begin{aligned}12x+2y+z+4t&=9\\5x+15y-10z+20t&=-5\end{aligned}$

   Which of the following matrices represents this system?
   

   Choose 1 answer:
   

   1. $\qquad \left[\begin{array} {ccc}12 & 2 & 1 & 4 & -9 \\5 & 15 & -10 & 20 & 5 \end{array} \right]$

   2. $\qquad \left[\begin{array} {ccc}12 & 2 & 4 & 1 & -9 \\5 & 15 & -10 & 20 & 5 \end{array} \right]$

   3. $\qquad \left[\begin{array} {ccc}2 & 12 & 1 & 4 & 9 \\5 & 15 & 10 & 20 & -5 \end{array} \right]$

   4. $\qquad \left[\begin{array} {ccc}12 & 2 & 1 & 4 & 9 \\5 & 15 & -10 & 20 & -5 \end{array} \right]$

3. Write the following system of equations as an augmented matrix.

   Represent each row and column in the order in which the variables and equations appear below.
   

   $\begin{aligned}10x-15y=5\\3x+2y=8\end{aligned}$

4. $\begin{aligned}3x+4y-2t&=-11\\8x-9y-2z+5t&=18\end{aligned}$

   Which of the following matrices represents this system?
   

   Choose 1 answer:
   

   1. $\qquad \left[\begin{array} {ccc}3 & 4 & -2 & 0 & 18 \\8 & -9 & -2 & 5 & -11 \end{array} \right]$

   2. $\qquad \left[\begin{array} {ccc}-11 & 2 & 4 & 0 & -2 \\8 & -9 & -2 & 5 & 18 \end{array} \right]$

   3. $\qquad \left[\begin{array} {ccc}3 & 4 & 0 & -2 & -11 \\8 & -9 & -2 & 5 & 18 \end{array} \right]$

   4. $\qquad \left[\begin{array} {ccc}3 & 4 & 1 & -2 & -11 \\8 & -9 & -2 & 5 & 18 \end{array} \right]$

Source: Khan Academy, https://www.khanacademy.org/math/algebra-home/alg-matrices/alg-representing-systems-with-matrices/e/represent-systems-with-matrices
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