\( \begin{array}{l}\text { A local high school held a two-day fundraiser selling lunches. The equations shown } \\ \text { represent the amount of money the school collected during the two days. }\end{array} \) \( \left\{\begin{array}{l}12 x+4 y=152 \\ 32 x+12 y=420\end{array}\right. \) In the equations, \( x \) represents the cost of a chicken lunch and \( y \) represents the cost of a vegetarian lunch. Which is the cost of the vegetarian lunch?

Cuál es la inversa de la matriz: \( \left[\begin{array}{lll}1 & 2 & 1 \\ 0 & 1 & 0 \\ 2 & 0 & 3\end{array}\right] \) a. \( \left[\begin{array}{ccc}-3 & 6 & 1 \\ 0 & 1 & 0 \\ 2 & 4 & -1\end{array}\right] \) b. \( \left[\begin{array}{ccc}-3 & 0 & 2 \\ 6 & 1 & 4 \\ 1 & 0 & 1\end{array}\right] \) c. \( \left[\begin{array}{ccc}3 & 0 & -2 \\ -6 & 1 & 4 \\ 1 & 0 & 1\end{array}\right] \) d. \( \left[\begin{array}{ccc}3 & -6 & 1 \\ 0 & 1 & 0 \\ -2 & 4 & 1\end{array}\right] \)

1) A picture should be centered on a wall. The picture is 3 feet wide. The wall is 15 feet wide. How much space should be on the left \( (x) \) and right \( (x) \) of the picture? \( x+3+x=15 \) \( 2 x+3=15 \) What is the value of \( x \) ?

15. Solve: \( |5 x+1|-9=-4 \)

\( \left.\begin{array}{l}1 \leftarrow \quad \begin{array}{l}\text { Write the augmented matrix for the system of linear equations. } \\ \begin{array}{rl}9 x+y+5 z & =5 \\ 7 x-3 y-z & =9 \\ x-6 y-5 z & =-4\end{array} \\ \text { Enter the augmented matrix. } \\ \square \square \square \square \square \square \square\end{array} \\ \square \square \square \square\end{array}\right] \)

16 Solve the system of equations using matrices. Use the Gaussian elimination method with back-substitution. \[ \begin{array}{r}x+y-z=-4 \\ 4 x-y+z=-1 \\ -x+5 y-4 z=1\end{array} \] The solution set is \( \{(\square, \square, \square)\} \). (Simplify your answers.)