If x x 2 1 + x 3 y y 2 1 + y 3 z z 2 1 + z 3 = 0 and x ,   y ,   z are all distinct, then x y z =

If xx21+x3yy21+y3zz21+z3=0 and x, y, z are all distinct, then xyz=
  1. -1
  2. 1
  3. 0
  4. 3

Solution

Given,

If xx21+x3yy21+y3zz21+z3=0

xx21yy21zz21+xx2x3yy2y3zz2z3=0

Taking x,y,z from C1,C2,C3 respectively 

xx21yy21zz21+xyz1xx21yy21zz2=0

By interchanging the columns twice

xx21yy21zz21+xyzxx21yy21zz21=0

xx21yy21zz211+xyz=0

R1R1-R2 & R2 R2-R3

x-yx2-y21-1y-zy2-z21-1zz211+xyz=0

x-yx-yx+y0y-zy-zy+z0zz211+xyz=0

x-yy-z1x+y01y+z0zz211+xyz=0

R1R1-R2

x-yy-z1-1x+y-y-z01y+z0zz211+xyz=0

x-yy-z0x-z01y+z0zz211+xyz=0

x-yy-z-x+z×11+xyz=0

x-yy-zz-x1+xyz=0

1+xyz=0 xyz

Hence, xyz=-1

Asked in: AP EAMCET 2021 (20 Aug Shift 2)

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