diketahui determinan dari matriks [ 5a -a] kebawah [ 3a -3] = -18, tentukan nilai a

-3(5a)-(-a)3a = -18
-15a + 3a^ = -18
3a^ - 15a + 18 =0. ÷3
a^ - 5a + 6 = 0
(a-3)(a-2) =0
a = 3 \/ a = 2

Matriks.

[tex]\displaystyle \begin{vmatrix} 5a &-a \\ 3a & -3 \end{vmatrix}=-18[/tex]
5a(-3) - (-a)(3a) = -18
-15a + 3a² + 18 = 0
3a² - 15a + 18 = 0
3(a² - 5a + 6) = 0
3(a - 2)(a - 3) = 0
a = 2 atau a = 3