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If a+b+c=0 then find value of (b+c)2bc+(c+a)2ca+(a+b)2ab\frac{(b + c)^2}{bc} + \frac{(c + a)^2}{ca} + \frac{(a + b)^2}{ab}bc(b+c)2​+ca(c+a)2​+ab(
Question

If a+b+c=0 then find value of (b+c)2bc+(c+a)2ca+(a+b)2ab\frac{(b + c)^2}{bc} + \frac{(c + a)^2}{ca} + \frac{(a + b)^2}{ab} ? ​

A.

8abc

B.

a2+b2+c2a^2+b^2+c^2​​

C.

2(a+b+c)22(a+b+c)^2​​

D.

3

Correct option is D

Given:

a + b + c = 0

Formula used:

a+b+c=0,then a3+b3+c3=3abc Thus, a3+b3+c3=3abca + b + c = 0, \text{then } a^3 + b^3 + c^3 = 3abc\\\ \\\text{Thus, } a^3 + b^3 + c^3 = 3abc​​

Solution:

a+b+c=0Then a+b=c, b+c=a and c+a=b(b+c)2bc+(c+a)2ca+(a+b)2ab =bc(a)2+ca(b)2+ab(c)2 =bca3+cab3+abc3 As we know, if a+b+c=0,then a3+b3+c3=3abc Thus, a3+b3+c3=3abc abc3abc=3abcabc=3a + b + c = 0\\\text{Then } a + b = -c, \, b + c = -a \, \text{and} \, c + a = -b\\\frac{(b + c)^2}{bc} + \frac{(c + a)^2}{ca} + \frac{(a + b)^2}{ab}\\\ \\= \frac{bc}{(-a)^2} + \frac{ca}{(-b)^2} + \frac{ab}{(-c)^2}\\\ \\= \frac{bc}{a^3} + \frac{ca}{b^3} + \frac{ab}{c^3}\\\ \\\text{As we know, if } a + b + c = 0, \text{then } a^3 + b^3 + c^3 = 3abc\\\ \\\text{Thus, } a^3 + b^3 + c^3 = 3abc\\\ \\\frac{abc}{3abc} = \frac{3abc}{abc} = 3​​


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