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If : a+b+c=14a + b + c = 14 and a2+b2+c2=96a^2 + b^2 + c^2 = 96, then (ab+bc+ca)(ab + bc + ca) is

Solution

✅ Correct Option: 2

Given:

a+b+c=14a + b + c = 14

a2+b2+c2=96a^2 + b^2 + c^2 = 96


Using the algebraic identity:

(a+b+c)2=a2+b2+c2+2(ab+bc+ca)(a + b + c)^2 = a^2 + b^2 + c^2 + 2(ab + bc + ca)


Substituting the given values:

(14)2=96+2(ab+bc+ca)(14)^2 = 96 + 2(ab + bc + ca)

196=96+2(ab+bc+ca)196 = 96 + 2(ab + bc + ca)


196−96=2(ab+bc+ca)196 - 96 = 2(ab + bc + ca)

100=2(ab+bc+ca)100 = 2(ab + bc + ca)

ab+bc+ca=1002ab + bc + ca = \dfrac{100}{2}

ab+bc+ca=50ab + bc + ca = 50

Therefore, (ab+bc+ca)=50(ab + bc + ca) = 50

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