Question

If x + y + z = 7 and xy + yz+ zx = 30, find x + y + z​

Answer 1

Step-by-step explanation:

your answer is x+y+z=7.

Answer 2

Here we see two things

1) The question itself has answer, that is x+y+z=7, when this is given there is no need of second equation. To find out x+y+z, the answer is 7.

2) if the question is wrong, and if we have to find out x^2+y^2+z^2, then there is no need to find

x+y+z.

And, to find out the value of x^2+y^2+z^2

here are the steps

(x+y+z)^2 = x^2+y^2+z^2+2 (xy+yz+zx)

(7)^2=x^2+y^2+z^2+2 (30)

49 = x^2+y^2+z^2+60

x^2+y^2+z^2=49-60

x^2+y^2+z^2 = -11