Question

a+b+c =9 ab+bc+ac=15 find the value of a²+b²+c²​

Answer 1

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

∴ (9)2 = a2 + b2 + c2 + 2(15)

81 = a2 + b2 + c2 + 30

∴ a2 + b2 + c2 = 81 – 30 = 51

Answer 2

Answer is 27

a₊b₊c=9

ab₊bc₊ca=15

a=3,b=3,c=3

ab=3₊3=9

bc=3₊3=9

ca=3₊3=9

a²₊b²₊c²=?

a²=3²,b²=3²,c²=3²

3²=9

3²=9₊9₊9

3²₊3²₊3²=9₊9₊9

27=27