Question

the value of A2+b2+c2, if a +b+c=13 and ab+bc+ca=27​

Answer 1

Answer:

215 is the value of a²+b²+c², if a +b+c=13 and ab+bc+ca=27

Answer 2

Given

a + b + c = 13

ab + bc + ca = 27

To find

The value of a² + b² + c²

The identities with use in this question

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

Where

a + b + c = 13 ,ab + bc + ca = 27

We get

(13)² = a² + b² + c² + 2(27)

169 = a² + b² + c² + 54

a² + b² + c²  = 169 - 54

a² + b² + c² = 115

Answer

a² + b² + c² = 115

More identities

(a + b)² = a² + b² + 2ab

(a - b)² = a² + b² - 2ab

(a + b)(a - b) = a² - b²

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