Test Index

CBSE Class 12 Math 2018 Solved Paper

© examsnet.com
Question : 13 of 29
Marks: +1, -0
Using properties of determinants, prove that
|111+3x1+3y1111+3z1| = 9 (3xyz + xy + yz + zx)
Solution:  
Let Δ = |111+3x1+3y1111+3z1|
Apply
R2 → R2−R1 , R3 → R3−R1
Δ = |111+3x3y0−3x03z−3x|
Expanding along R1 , we get
Δ = 9xz + 9xy + 9yz + 27xyz
= 9 (xz + xy + yz + 3xyz)
© examsnet.com
Go to Question:
Prev Question
Next Question