Question

If $\left| \begin{matrix} a & b & a + b \\ b & c & b + c \\ a + b & b + c & 0 \end{matrix} \right| = 0$; then $a,b,c$ are in.

• A. A. P.
• B. G. P.
• C. H. P.
• D. None of these

Answer 1

Answer: (B)

G. P.

Answer 2

Let a,b,c are in G.P. and assume

$A_{13} = - 5$

$\therefore A = \left| \begin{matrix} 1 & 2 & 3 \\ 2 & 4 & 6 \\ 3 & 6 & 0 \end{matrix} \right| = 0$ .