Evaluate $\begin{vmatrix} x & x + 1 \\ x - 1 & x \end{vmatrix}$.
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → 1 ##
We have
$\begin{vmatrix} x & x + 1 \\ x - 1 & x \end{vmatrix} = x(x) - (x + 1)(x - 1)$
$= x^2 - (x^2 - 1) = x^2 - x^2 + 1 = 1$