To simplify the expression, we can start by simplifying each term separately.

1) Simplifying 2/√3-1:
To simplify this term, we need to rationalize the denominator. Multiplying both the numerator and denominator by √3, we get:
(2/√3)(√3/√3) - 1(√3/√3)
= (2√3/3) - (√3/√3)
= (2√3 - √3)/√3
= √3/√3
= 1

2) Simplifying √27:
√27 can be simplified by factoring 27 as 9 * 3:
√27 = √(9 * 3)
= √9 * √3
= 3√3

3) Simplifying 3/√3:
To simplify this term, we also need to rationalize the denominator. Multiplying both the numerator and denominator by √3, we get:
(3/√3)(√3/√3)
= (3√3/3)
= √3

Now, we can substitute the simplified terms back into the expression:
1 - 3√3 + √3
= 1 - 2√3