√12 + 6√1又1/2 - (√3-9/4 - √24)
=√2²*3 + 6√3/2 - (√3-9/4 - √2²*6)
=2√3 + 3√6 - √3+9/4 +2√6
=2√3- √3 + 3√6 +2√6+9/4
=5√6+9/4