Question

por favor me ajudem a resolver essas questões de matriz.
coloquei a foto das questões...​

Answer 1

Resposta:

1)

A + B =

$\left[\begin{array}{ccc}-2+4&8+16&5-10\\3+6&10-20&0+0\\1+1&-8+5&6+3\end{array}\right] =\left[\begin{array}{ccc}2&24&-5\\9&-10&0\\2&-3&9\end{array}\right]$

2)

$\left[\begin{array}{ccc}0&3&0\\-2&3&1\\4&-2&5\end{array}\right] \begin{matrix}0&3\\ -2&3\\ 4&-2\end{matrix}=\\ \\\\ Diagonal~~principal ~menos~~diagonal~~secund\'aria\\ \\ 0+12+0-(0-0-30)=\\ \\ 12-(-30)=12+30=\boxed{42}$

3)

-2B=

$\left[\begin{array}{ccc}-2(-2)&-2(8)&-2(5)\\-2(3)&-2(10)&-2(0)\\-2(1)&-2(8)&-2(6)\end{array}\right] =\left[\begin{array}{ccc}4&-16&-10\\-6&-20&0\\-2&-16&-12\end{array}\right]$

4)

$7x-5(x+2)=0\\ \\ 7x-5x-10=0\\ \\ 2x=10\\ \\ x=10:2\\ \\\boxed{ x=5}$