Respostas

2013-07-27T16:57:43-03:00
Calculando det J:
Pela regra de Sarrus:

\begin{bmatrix} 0 & 6 &-1&0&6\\ 2&3&1&2&3\\ 4&8&-7&4&8 \end{bmatrix} \\ -12\mid0\mid-84\\
~~~~~~~~~~~~-21\mid24\mid-16\\
 \det{J}=-(-12+0-84)+(-21+24-16)\\
=-(-96)+(-13)=\\
=96-13=83

\begin{bmatrix} 8 & 0 &2&8&0\\ 1&1&-4&1&1\\ 3&2&5&3&2 \end{bmatrix} \\ ~~6\mid-64\mid5\\ ~~~~~~~~~~~~40\mid-12\mid4\\ \det{L}=-(6-64+5)+(40-12+4)\\ =-(-53)+(32)=\\ =53+32=85

e
K=\begin{bmatrix}2&5\\
-3&y
\end{bmatrix}\\
\det{K}=2y-(-15)=2y+15


\det{J}+\det{L}=\det{K}\\
83+85=2y+15\\
2y+15=168\\
2y=153\\
y=76,5