Let , and be complex numbers such that . If and , find the value of .
Solution
Manipulate the equations to get a common denominator: ; similarly, and . Thus $\frac{1}{x-1}+\frac{1}{y-1}+\frac{1}{z-1} =1 \Rightarrow (y-1)(z-1)+(x-1)(z-1)+(x-1)(y-1) =(x-1)(y-1)(z-1) \Rightarrow x y+y z+z x-2(x+y+z)+3 =x y z-(x y+y z+z x)+(x+y+z)-1 \Rightarrow x y z-2(x y+y z+z x)+3(x+y+z)-4 =0 \Rightarrow x y z-2(67)+3(2010)-4 =0 \Rightarrow x y z =-5892
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