12√18÷2√3
12 sqrt[2 x 9] / 2sqrt(3)
3x12sqrt(2) / 2sqrt(3)
36sqrt(2) / 2sqrt(3) divide both sides by 2
18sqrt(2) / sqrt(3) multiply both numerator and denominator by sqrt(3)
18sqrt(6) / 3 divide .....................................................by 3
=6sqrt(6)