Skip to main contentSkip to solution

If ∣2x24x∣=10\begin{vmatrix} 2x & 2 \\ 4 & x \end{vmatrix} = 10, then xx is:

Solution

✅ Correct Option: 2

Compute determinant: 2x⋅x−4⋅2=2x2−82x \cdot x - 4 \cdot 2 = 2x^2 - 8. Set equal to 10: 2x2−8=102x^2 - 8 = 10, so x2=9x^2 = 9, giving x=±3x = \pm 3.

Keyboard Shortcuts

  • Left arrow: Previous question
  • Right arrow: Next question
  • S key: Jump to solution
  • Q key: Jump to question