Question

me ajudem,é só até amanhã

Answer 1

Segue a resolução passo-a-passo;

3°)

$A=\left[\begin{array}{ccc}1&0&2\\3&4&1\end{array}\right]$

$B=\left[\begin{array}{ccc}1&1&4\\2&-1&0\end{array}\right]$

$A-4B$

$=\left[\begin{array}{ccc}1&0&2\\3&4&1\end{array}\right] -4\cdot\left[\begin{array}{ccc}1&1&4\\2&-1&0\end{array}\right]$

$=\left[\begin{array}{ccc}1&0&2\\3&4&1\end{array}\right] +\left[\begin{array}{ccc}-4&-4&-16\\-8&4&0\end{array}\right]$

$=\left[\begin{array}{ccc}(1-4)&(0-4)&(2-16)\\(3-8)&(4+4)&(1+0)\end{array}\right]$

$=\left[\begin{array}{ccc}-3&-4&-14\\-5&8&1\end{array}\right]$

4°)

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

$=\left[\begin{array}{ccc}1\cdot 2+3\cdot 2+3\cdot 0&1\cdot 1+2\cdot 5+3\cdot 2\\2\cdot 2+0\cdot 3+1\cdot 0&2\cdot 1+0\cdot 5+1\cdot 2\\1\cdot 2+2\cdot 3+0\cdot 0&1\cdot 1+2\cdot 5+0\cdot 2\end{array}\right]$

$=\left[\begin{array}{ccc}8&17\\4&4\\8&11\end{array}\right]$

Se estiver com alguma dúvida, pode me chamar nos comentários. Bons estudos ^~