Question 21

If (a + b + c) = 6 and $$a^2 + b^2 + c^2$$ = 14, then (ab + bc + ca) = ?

Solution

Share

$$(a + b + c)^2 =a^2 + b^2 + c^2 + 2(ab + bc + ca)$$

$$(6)^2 =14 + 2(ab + bc + ca)$$

36-14 = 2(ab + bc + ca)

(ab + bc + ca) = 11

Get AI Help

Create a FREE account and get:

  • Download RRB Study Material PDF
  • 45+ RRB previous papers with solutions PDF
  • 300+ Online RRB Tests for Free

Join CAT 2026 course by 5-Time CAT 100%iler

Crack CAT 2026 & Other Exams with Cracku!

Enroll Now
Ask AI

Ask our AI anything

AI can make mistakes. Please verify important information.