In each of   the following, determine whether the given values are solutions of the given   equation or not: `x^2-3x+2=0,\ \ x=2,\ x=-1`  (ii) `x^2+x+1=0,\ \ x=0,\ x=1`  (iii) `x^2-3sqrt(3)x+6=0,\ \ x=sqrt(3),\ \ x=-2sqrt(3)`  (iv) `x+1/x=(13)/6,\ \ x=5/6,\ \ x=4/3`
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