Question

if x+y-z= 5 and x^2+y^2+z^2= 29, find the value of xy-yz-zx

Answer 1

Step-by-step explanation:

Answer:

xy+yz+zx= 30

Step-by-step explanation:

Given \: x+y+z=10--(1)\\x^{2}+y^{2}+z^{2}=40---(2)

/* On Squaring both sides of equation (1) , we get

(x+y+z)^{2}=(10)^{2}

\implies x^{2}+y^{2}+z^{2}+2xy+2yz+2zx=100

\implies 40+2(xy+yz+zx)=100

\implies 2(xy+yz+zx)=100-40

\implies 2(xy+yz+zx)=60

\implies xy+yz+zx= \frac{60}{2}

\implies xy+yz+zx= 30

Therefore,

xy+yz+zx= 30

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Answer 2

Answer is 30 in the photo check it out.......