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If ab+c=bc+a=ca+b=k\dfrac{a}{b+c}=\dfrac{b}{c+a}=\dfrac{c}{a+b}=k then value of kk is

Solution

✅ Correct Option: 2

Given: ab+c=bc+a=ca+b=k\frac{a}{b+c} = \frac{b}{c+a} = \frac{c}{a+b} = k

Let's say:

a=k(b+c)a = k(b+c) ...(1)

b=k(c+a)b = k(c+a) ...(2)

c=k(a+b)c = k(a+b) ...(3)

From (1): ak=b+c\frac{a}{k} = b + c

From (2): bk=c+a\frac{b}{k} = c + a

From (3): ck=a+b\frac{c}{k} = a + b

Adding all equations:

a+b+ck=2(a+b+c)\frac{a+b+c}{k} = 2(a+b+c)

Therefore:

1k=2\frac{1}{k} = 2

k=12k = \frac{1}{2}

If we subtract (2) from (1), we get :

a−b=k(b−a)a-b = k(b-a)

(a−b)=−k(a−b)(a-b)=-k(a-b)

1=−k1=-k

k=−1k=-1

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