1.

Consider the system of equations `(a -1) x -y -z = 0` `x -(b -1) y +z = 0` `x + y - (c -1) z = 0` Where a, b and c are non-zero real number Statement1 : If x,y,z are not all zero, then `ab + bc + ca + abc` Statement 2 : `abc ge 27`A. Statement 1 is true, Statement 2 is true, Statement 2 is a correct explanation for Statement 3B. Statement 1 is true, Statement 2 is true, Statement 2 is not a correct explanation for Statement 3C. Statement 1 is true, Statement 2 is FalseD. Statement 1 is False, Statement 2 is true

Answer» Correct Answer - B
It is given that x,y,z are not all zero. So, the given system of equation has a non-trivial solutions.
`:. |(a -1,-1,-1),(1,-(b -1),1),(1,1,-(c -1))| = 0`
`rArr |(a,0,-1),(0,-b,1),(c,c,1-c)| = 0 " " [("Applying " C_(1) rarr C_(1) - C_(3)),(C_(2) rarr C_(2) - C_(3))]`
`rArr a(-b + bc -c) - (0 + bc) = 0`
`rArr ab + bc + ac = abc`
Using `A.M. ge G.M`., we have
`(ab + bc + ca)/(3) ge (abc)^(2//3)`
`rArr abc ge 3 (abc)^(2//3) rArr abc ge 27`
So, both statements are true


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