Question

Alguém resolve para mim?

Answer 1

         $AxX= \left[\begin{array}{ccc}1&&5\\&&\\-1&&2\end{array}\right] x \left[\begin{array}{ccc}&a&\\&&\\&b&\end{array}\right] = \left[\begin{array}{ccc}&2a+5b&\\&&\\&-a+2b&\end{array}\right] \\ \\ \\ \left[\begin{array}{ccc}&2a+b&\\&&\\&-a+2b&\end{array}\right] = \left[\begin{array}{ccc}&5&\\&&\\&2&\end{array}\right]$


             2a + b = 5            (1)
             - a + 2b = 2          (2)
Resolvendo sistema (1) (2)
    (2) x 2
             - 2a + 4b = 4          (3)
     (1) + (3)
                   5b = 9
                                       b = 9/5
Em (2)    - a + 2(9/5) = 2
                 a = 18/5 - 2
                    = 18/5 - 10/5
                     = 8/5
                                       a = 8/5

                       $X= \left[\begin{array}{ccc}& \frac{8}{5} &\\&&\\& \frac{9}{5} &\end{array}\right]$

Answer 2

$A * X = \left[\begin{array}{ccc}1&&5\\&&\\-1&&2\end{array}\right] * \left[\begin{array}{ccc}&a&\\&&\\&b&\end{array}\right] = \left[\begin{array}{ccc}&2a+ 5b&\\&&\\&-a+2b&\end{array}\right] \\ \\ \\ \\ \\ \\ A* X = \left[\begin{array}{ccc}&5&\\&&\\&2&\end{array}\right]$
2a + 5b = 5
(*2) -a + 2b = 2(*2)
-2a + 4b = 4

2a + 5b = 5
-2a + 4b = 4
-----------------
  b = 1
2a + 5 * 1 = 5
2a + 5 = 5
2a = 5 - 5
2a = 0
a = 0
b = 1