if x+y-z= 5 and x^2+y^2+z^2= 29, find the value of xy-yz-zx
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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 is 30 in the photo check it out.......