Question

Find the value of a+b+c if a²+b²+c² = 35, ab+bc+ca=23

Answer 1

a + b + c = 9

Explanation:

Note that

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

(a + b + c)² = 35 + 2(23) = 35 + 46 = 81

Take the square root of both sides

a + b + c =
`√(81)` = 9

Answer 2

Here is your answer

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

(a+b+c)^2= 35 + 2×23= 35+46

(a+b+c)^2= 81= 9^2

(a+b+c) = 9

HOPE IT IS USEFUL