For a 2×2 matrix acbd, the determinant equals (a×d)−(b×c).
Calculate the left side determinant:
2x85x
=(2x)(x)−(5)(8)
=2x2−40
Calculate the right side determinant:
340−8
=(3)(−8)−(0)(4)
=−24
Set the determinants equal:
2x2−40=−24
2x2=16
x2=8
x=±8
x=±22
Therefore, the values of x are ±22.