Question

If a+b+c = 5, ab+bc+ac = 10 find a2+b2+c2

Answer 1

a + b + c = 5

Square on both sides,

(a + b + c)² = 5²

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By formula,
(a+b+c)²=a²+b²+c²+2(ab+bc+ca)
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a² + b² + c² +2(ab + bc +ca) = 25

a² + b² + c² +2(10) =25

a² + b² + c² =25-20=5

I hope this will help you


-by ABHAY

Answer 2

(a+b+c)^2=25
a^2+b^2+c^2+2(ab+bc+ca)=25
a^2+b^2+c^2+20=25

a^2+b^2+c^2=5