If `|[ x^n ,x^(n+2) ,x^(2n)],[1 ,x^a , a ],[x^(n+5),x^(a+6),x^(2n+5)]|=0,AAx in R, where . n in N ,` then value of a is a. `n` b. `n-1` c. `n+1` d. none of these

Options

A. n
B. n-1
C. n+1
D. none of these

Explanation

Taking `x^(5)` common from last row we bet
`x^(5) |{:(x^(n),,x^(n+2),,x^(2n)),(1,,x^(a),,a),(x^(n),,x^(a+1),,x^(2n)):}|=0 ,AA x in R`
`rArr a +1 = n+2 " or " a = n+1`
(as it will make first and third row is identical )