Question

if X + Y + Z = 10 and X square + Y square + Z square is equal to 30 find the value of xy + yz plus zx​

Answer 1

Answer:

Step-by-step explanation:

We know that x^2 +y^2 +z^2 =30

We know that in this question only positive no. r there

So I just checked the perfect square no. Which comes before 30

So got = 1,4,9,16,25

Then started to add each and every no. To no.

So I only got = 1+4+25=30

So,

X = 1

Y = 2

Z = 5

Answer 2

Answer:

Step-by-step explanation:

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

So

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

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

Substituting the respective values

xy+yz+zx =[ (10)^2 - 30]/2

=(100-30)/2

=70/2

=35

Hope it is clear

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