5/(1+√3)÷(2/3) = [5*(1-√3)]/[(1+√3)*(1-√3)] ×(3/2)
=-(5-5√3)/2 × (3/2)
=-(15-15√3)/4
5/(1-√3)÷(2/3) = [5*(1+√3)]/[(1-√3)(1+√3)] × (3/2)
= -(5+5√3)/2 × (3/2)
= -(15+15√3)/4