When a matrix is raised to a power, the determinant is also raised to that same power.
∣A3∣=∣A∣3
Given that ∣A3∣=64:
∣A∣3=64
∣A∣=364
∣A∣=4
For a 2×2 matrix [acbd], the determinant is ad−bc.
For matrix A=[p−4−3p]:
∣A∣=(p)(p)−(−3)(−4)
∣A∣=p2−12
Since ∣A∣=4:
p2−12=4
p2=16
p=±4
Therefore, the value of p is ±4.