Question

x + y+ z = 9 , xy + y z + z x = 40 find the value of x²+y²+z²

2 ​

Answer 1

Answer:

x + y+ z = 9

squaring both sides

x^2 + y^2 + z^2 +xy + yz+ zx = 81

now xy +yz + zx= 40   (given)

x^2 + y^2 + z^2 + 40 = 81

x^2 + y^2 + z^2 = 81 - 40

x^2 + y^2 + z^2 = 41

hope this helps you!!

Answer 2

(x+y+z)² = x²+y²+z²+ 2(xy+yz+zx)

putting all the values we get

=> x²+y²+z²= 9²-2(40) = 81-80 = 1.