Soal Matematika Matriks kelas 3 SMA

nomor 9, *sekalian tanya, nomor 3 suku y nya mana? yang diketahuinya hanya suku x

A . B

[tex] \left[\begin{array}{ccc}1&2\\3&4\end{array}\right] [/tex] [tex] \left[\begin{array}{ccc}-6&-5\\5&4\end{array}\right] [/tex]  =  [tex] \left[\begin{array}{ccc}4&3\\2&1\end{array}\right] [/tex]

maka invers A.B
[tex] \frac{1}{4-6} [/tex] [tex] \left[\begin{array}{ccc}1&-3\\-2&4\end{array}\right] [/tex]

[tex] \frac{1}{-2} [/tex] [tex] \left[\begin{array}{ccc}1&-3\\-2&4\end{array}\right] [/tex]

[tex] \left[\begin{array}{ccc} \frac{1}{-2} & \frac{3}{2} \\1& \frac{1}{-2} \end{array}\right] [/tex]


nomor 3

3 + (-3x) = -9
-3x = -12
x = 4

5+4y+x = 17
5 + 4y + 4 = 17
4y = 8
y = 2