Mohon bantuannya yaa, soal terlampir

A = [tex] \left[\begin{array}{cc}x&-3\\3x&x\end{array}\right] [/tex]

|A| = 10
x² - (-3)(3x) = 10
x² + 9x - 10 = 0
(x + 10)(x - 1) = 0
x = -10   atau   x = 1

No.33
ada di gambar