Question

If a+b+c=9 and ab+bc+ca=40.find a^2+b^2+c^2

Answer 1

a^2 + b^2 + c^2 = ? 
using: (a + b + c)^2 = a^2 + b^2 + c^2 + 2(ab + bc + ca) 
a^2 + b^2 + c^2 = 9^2 - 2(40) 
= 81 - 80 
= 1 

Hope This Helps :)

Answer 2

Given, a + b + c = 9 and ab + bc + ca = 40
We know that,
(a + b + c)2 = a 2 + b 2 + c 2 + 2ab + 2bc + 2ca
⇒ a 2 + b 2 + c 2 = (a + b + c)2 – 2 (ab + bc + ca)
⇒ a 2 + b 2 + c 2 = (9)2 – 2 × 40 = 81 – 80 = 1 [a + b + c = 9] and[ ab + bc + ca = 40]
Thus, the value of a 2 + b 2 + c 2 is 1.


If you like it please tap on brainlist. ...