Question

If x+y+z=6 and x^2+y^2+z^2=14,then find the value of xy+yz+zx​

Answer 1

Step-by-step explanation:

(x+y+z)^2 = x^ 2 + y^2 + z^2 + 2(x+y+z)

so put the given value from question

we get

6^2 = 14 + 2(x+y+z)

on solving

36-14 = 2(x+y+z)

22 = 2(x+y+z)

so finally

x+y+z = 11