diket: matriks A= 2x 1. matriks B= -6 -7 x² -3. -x 5 jika determinan A = determinan B , maka nilai x adalah??

jawab

[tex] A\,=\,\left[\begin{array}{ccc}2x&1\\x^2&-3\end{array}\right] [/tex]

[tex] B\,=\,\left[\begin{array}{ccc}-6&-7\\-x&-5\end{array}\right] [/tex]

[tex]det\,A\, =\, det\, B[/tex]

[tex]2x(-3)-x^2 (1) = -6(5) -(-x)(-7) [/tex]

[tex]-6x -x^2 =-30 -7x [/tex]

[tex] x^2 + 6x - 7x - 30 = 0[/tex]

[tex]x^2 - x - 30 = 0 [/tex]

[tex](x-6)(x+5)= 0[/tex]

[tex]x - 6 = 0 \, atau\, x + 5 = 0[/tex]

[tex]x = 6 \, atau\,x\,= -5[/tex]