Discuss Forum

1. a+b +c=9 , a2+b2+c2=29  

  • A. 52
  • B. 52
  • C. 52
  • D. 52

Answer: Option C

Explanation:

a + b + c = 9,

a² + b² + c² = 29,

ab + bc + ca = ?

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

বা, ab + bc + ca = {(a + b + c)² - (a² + b² + c² )}/2

= (81 - 29) / 2

= 26

Post your comments here:

Name:
Mobile:
Email:(Optional)

» Your comments will be displayed only after manual approval.