Question

x+y+z=2 si xy+xz+yz=0,x patrat + y patrat + z patrat = ?

Answer 1

Răspuns:

Explicație pas cu pas:

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

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

4 =  x^2 + y^2 + z^2 + 0

x^2 + y^2 + z^2  = 4