Determine values of \( k \) will the matrix below be nonsingulay. \( B=\left[\begin{array}{lll}2 & 2 & 1 \\ 3 & 1 & 3 \\ 1 & 3 & k\end{array}\right] \)

Expand. Your answer should be a polynomial in standard form. \( (3 b-4)(b+2)=\square \)

Determine the value of \( C \) that makes each expression a Perfect square. \( x^{2}+14+c \)

9.- Desarrollar: \( (13 x-17 y)(17 y+13 x)= \)

138. Hallar el resto de la división \( \frac{[(x+4)(x+3)(x+2)(x+1)+3]^{4}}{x^{2}+5 x+5} \) \( \begin{array}{lllll}\text { a. } 25 & \text { b. } 34 & \text { c. } 43 & \text { d. } 27 & \text { e. } 6\end{array} \)

6. Al resolver el sistema \( \left\{\begin{array}{l}5 x+6 y=20 \\ 4 x-3 y=-23\end{array}\right. \) \( \begin{array}{rlrl}5 x . x=2 & \text { b. } x=-2 & \text { c. } x=5 & \text { d. } x=-5 \\ y=5 & y=5 & y=-2 & y=2\end{array} \)