Question

If x2+y2+z2 = 40 and xy + yz + zx = 30, then x +y + z is equal to

Answer 1

Step-by-step explanation:

(x+y+z)²=x²+y²+z²+2xy+2yz+2zx

= 40. +2(xy+yz+zx)

= 40. +2(30)

= 40. + 60

=100

x+y+z. =root 100

=10