Question

VALENDO 28 PONTOS.... me ajudem por favor no exercício da foto.... MAIS POR FAVOR tentam resover usando 2.L2-L1 ( foi so um exemplo) onde no exemplo o 2 é oq multiplica e L2 e L3 sao as linhas

Answer 1

$\left[\begin{array}{cccc}1&2&-1&2\\2&-1&1&3\\1&1&1&6\end{array}\right]$

L2 = L2 - 2L1

$\left[\begin{array}{cccc}1&2&-1&2\\0&-5&3&-1\\1&1&1&6\end{array}\right]$

L3 = L3 - L1

$\left[\begin{array}{cccc}1&2&-1&2\\0&-5&3&-1\\0&-1&2&4\end{array}\right]$

L2 = L2.(-1/5)

$\left[\begin{array}{cccc}1&2&-1&2\\0&1&-\frac{3}{5} &\frac{1}{5} \\0&-1&2&4\end{array}\right]$

L3 = L3 + L2

$\left[\begin{array}{cccc}1&2&-1&2\\0&1&-\frac{3}{5} &\frac{1}{5} \\0&0&\frac{7}{5} &\frac{21}{5} \end{array}\right]$

L3 = L3.(5/7)

$\left[\begin{array}{cccc}1&2&-1&2\\0&1&-\frac{3}{5} & \frac{1}{5} \\0&0&1&3\end{array}\right]$

L2 = L2 + 3/5L3

$\left[\begin{array}{cccc}1&2&-1&2\\0&1&0&2\\0&0&1&3 \end{array}\right]$

L1 = L1 + L3

$\left[\begin{array}{cccc}1&2&0&5 \\0&1&0&2\\0&0&1&3\end{array}\right]$

L1 = L1 - 2L2

$\left[\begin{array}{cccc}1&0&0&1 \\0&1&0&2\\0&0&1&3\end{array}\right]$

Logo, x = 1, y = 2 e z = 3