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if a,b,ca, b, ca,b,c are three unequal numbers and ∣0x−ax−bx+a0x−cx+bx+c0∣=0\left| \begin{array}{ccc}0 & x - a & x - b \\x + a &
Question

if a,b,ca, b, c are three unequal numbers and 0xaxbx+a0xcx+bx+c0=0\left| \begin{array}{ccc}0 & x - a & x - b \\x + a & 0 & x - c \\x + b & x + c & 0 \\\end{array}\right| = 0 then xx is​

A.

aa​​

B.

0

C.

cc​​

D.

bb​​

Correct option is B

Solution:

Given:0xaxbx+a0xcx+bx+c0=0Expanding along the first row:Δ=00xcx+c0(xa)x+axcx+b0+(xb)x+a0x+bx+c=(xa)[(x+b)(xc)]+(xb)(x+a)(x+c)=(xa)(x+b)(xc)+(xb)(x+a)(x+c)Try x=0:=(a)(b)(c)+(b)(a)(c)=abcabc=0x=0\textbf{Given:} \\\begin{vmatrix}0 & x - a & x - b \\x + a & 0 & x - c \\x + b & x + c & 0\end{vmatrix} = 0\\[10pt]\textbf{Expanding along the first row:} \\\Delta = 0 \cdot \begin{vmatrix}0 & x - c \\x + c & 0\end{vmatrix}- (x - a) \cdot \begin{vmatrix}x + a & x - c \\x + b & 0\end{vmatrix}+ (x - b) \cdot \begin{vmatrix}x + a & 0 \\x + b & x + c\end{vmatrix}\\[10pt]= - (x - a)\left[ - (x + b)(x - c) \right] + (x - b)(x + a)(x + c)\\[10pt]= (x - a)(x + b)(x - c) + (x - b)(x + a)(x + c)\\[10pt]\textbf{Try } x = 0:\\= (-a)(b)(-c) + (-b)(a)(c) = abc - abc = 0\\[10pt]\boxed{x = 0}


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