Diketahui Persamaan Matriks [tex] \left(\begin{array}{ccc}1&1\\a&2\end{array}\right) \left(\begin{array}{ccc}x\\y\end{array}\right) = \left(\begin{array}{
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Diketahui Persamaan Matriks [tex] \left(\begin{array}{ccc}1&1\\a&2\end{array}\right) \left(\begin{array}{ccc}x\\y\end{array}\right) = \left(\begin{array}{ccc}8\\4\end{array}\right) [/tex].
Jika determinan dari [tex] \left(\begin{array}{ccc}1&1\\a&2\end{array}\right) = 1 [/tex], nilai x + y adalah...
a.16
b.12
c.8
d.4
e.0
Jika determinan dari [tex] \left(\begin{array}{ccc}1&1\\a&2\end{array}\right) = 1 [/tex], nilai x + y adalah...
a.16
b.12
c.8
d.4
e.0
1 Jawaban
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1. Jawaban Takamori37
[tex] \left|\begin{array}{cc}1&1\\a&2\end{array}\right|=1 \\ 2-a=1 \\ a=1[/tex]
[tex]Dikalikan, didapat: \\ x+y=8 \\ x+2y=4 \\ -$Kurangi$- \\ -y=4 \\ y=-4 \\ x+y=8 \\ x+(-4)=8 \\ x-4=8 \\ x=12 \\ \\ x+y=12+(-4)=12-4=8[/tex]