For a 2×2 matrix acbd, the determinant is calculated as:
ad−bc
For the left side: x182x
=x×x−2×18
=x2−36
For the right side: −4−8−2−4
=(−4)×(−4)−(−2)×(−8)
=16−16
=0
The equation becomes:
x2−36=0
x2=36
x=±6
Therefore, x=6 or x=−6
Both options (B) x=−6 and (D) x=6 are correct.
The answer is (B) and (D).