Question

If x + y-z = 4 and x2 + y2 + z2 = 30, then find the
value of xy - yz - Zx.​

Answer 1

Step-by-step explanation:

x+y-z=4

x^2+y^2+z^2=30

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

(4)^2 = 30+2(xy-yz-zx)

16 = 30+2(xy-yz-zx)

2(xy-yz-zx) = 14÷2

xy-yz-zx = 7