Question

if a^2 + b^2 + c^2 = 29 and a + b + c =9, find ab+ bc + ca

Answer 1

Answer:

26

Step-by-step explanation:

Given:

a² + b² + c² = 29.

a + b + c = 9

To find:

ab + bc + ca

Solution:

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

(9)² = 29 + 2(ab + bc + ca)

81 -29 = 2(ab + bc + ca)

52/2 = ab + bc + ca

26 = ab + bc + ca.