\( X=\left[\begin{array}{rr}x+y-1 & 0 \\ 0 & 3\end{array}\right] \) and \( Y=\left[\begin{array}{rr}5 & 0 \\ 0 & 2 x-3 y-7\end{array}\right] \) The value(s) of \( y \) for which the matrices \( X^{T} \) and \( Y \) have no inverses is/are given by: \( \begin{array}{l}k=\frac{2}{5} \\ \\ y=-2\end{array} \) and \( y=k \) \( y=1 \)

(i) \( 5 x^{2}-17 x+12 x^{3} \)

los \( \begin{array}{l}\text { 6. Analiza la siguiente expresión y completa con } \\ \text { terminos que faltan: }\end{array} \) \[ (\square+4)\left(x^{2}-5\right)=x^{4}-\square-20 \]

lynomial whose factors are \( (x-1),(x+1) \) and \( (x-2) \)

(2) \( -816(+461-899)+499 \)

Hence, or otherwise, determine the inverse of the matrix \( \left[\begin{array}{rr}2 & -5 \\ -2 & 7\end{array}\right] \), and solve the equation \( x\left[\begin{array}{c}2 \\ -2\end{array}\right]+y\left[\begin{array}{r}-5 \\ 7\end{array}\right]=\left[\begin{array}{c}2 \\ -10\end{array}\right] \)