Question

If x + y+ z =10 and ^ + ^2+^2=40,then find the value of ( i) xy + yz + zx (ii) ^3 + ^3+^3 - 3xyz

Answer 1

Answer:

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

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

xy + yz + zx = 30

x^3 + y^3 + z^3 - 3xyz = (x+y+z) (x^2 + y^2 + z^2 - xy - yz - zx) = 10 (40-30) = 100

Step-by-step explanation:

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