Question

If x+y+z= 10 and x^2 +y^2+z^2=40 find xy+yz+xz

Answer 1

Answer:

Step-by-step explanation:

(X+Y+Z)^2=X^2+Y^2+Z^2+2(XY+YZ+ZX)

(10)^2=40+2(XY+YZ+ZX)

100=40+2(XY=YZ=ZX)

100-40=2(XY+YZ+ZX)

60/2=XY+YZ+ZX

30=XY+YZ+ZX