Question

If a+b+c =12 and a square +b square +c square =64 find the value of ab+bc+ca

Answer 1

Here's your answer...

Given,

a + b + c = 12

a^2 + b^2 + c^2 = 64

Then

We know that,

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

Substitution

(12)^2 = 64+2(ab+bc+ca)

144 = 64 + 2(ab+bc+ca)

144-64 = 2(ab+bc+ca)

80 = 2(ab+bc+ca)

80/2 = ab+bc+ca

40 = ab+bc+ca

The value of ab+bc+ca is 40

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Hope this helps you....