Question

if a+b+c =12 and a^2+b^2c^2=64 then find the value of ab+bc+cb

Answer 1

(a+b+c)^2=a^2+b^2+c^2+2(ab+bc+ac)
(12)^2=64+2(ab+bc+ac)
144-64=2(ab+bc+ac)
80/2=ab+bc+ac
ab+bc+ac=40

Answer 2

a+b+c=12-----›(i)
a²+b²+c²=64------›(ii)

By using formula,

(a+b+c)² = a²+b²+c²+2(ab+bc+ca)

substitute the values of (i) & (ii)

we get

12²=64+2(ab+bc+ca)

144-64÷2= ab+bc+ca

40=ab+bc+ca.

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#HAKUNA MATATA @ Akshaymas.