If x is a positive integer, then $\begin{vmatrix}x! & (x+1)! & (x+2)!\\(x+1)! & (x+2)! & (x+3)!\\(x+2)! & (x+3)! & (x+4)!\end{vmatrix}$ is equal to
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$2x!(x+1)!$ $2x!(x+1)!(x+2)!$ $2x!(x+3)!$ $2(x+1)!(x=2)!(x+3)!$ |
$2x!(x+1)!(x+2)!$ |
The correct answer is option (2) : $2x!(x+1)!(x+2)!$ Let Δ be the value of the given determinant. Then, $Δ=\begin{vmatrix}x! & (x+1)! & (x+2)!\\(x+1)x! & (x+2)(x+1)! & (x+3)(x+2)!\\(x+2)(x+1)x! & (x+3)(x+2)(x+1)! & (x+4)(x+3)(x+2)!\end{vmatrix}$ $⇒Δ=x!(x+1)!(x+2)!$ $\begin{vmatrix}1 & 1 & 1\\x+1 & x+2 & x+3\\(x+1)(x+2) & (x+2)(x+3) & (x+3)(x+4)\end{vmatrix}$ $⇒Δ=x!(x+1)!(x+2)!\begin{vmatrix}1 & 0 & 0\\x+1 & 1 & 2\\(x+1)(x+2) & 2(x+2) & 4x+10\end{vmatrix}$ $⇒Δ=2x!(x-1)!(x+2)!$ |