Tolong di jawab dengan benar

misal
A = [tex] \left[\begin{array}{cc}a&b\\c&d\end{array}\right] [/tex]
maka
Det(A) = ad - bc
-------------------------------------------------------------

5(2 - 3x) - 4(4x + 2) = 64
10 - 15x - 16x - 8 = 64
-31x + 2 = 64
-31x = 64 - 2
-31x = 62
x = -2

jadi
x² = (-2)² = 4