(1)(√6-2√15)×√3-6√1/2=3√2-2×3√5-6×√2/2=3√2-6√5-3√2=-6√5
(2)√12÷√6×√1/6=√2×√6/6=2√3/6=√3/3
(3)(√48-√1/6)÷√3=(4√3-√6/6)÷√3=4-√2/6
(4)(√7-2)^2+(2-√3)(2+√3)=11-4√7+1=12-4√7
(5)√12/√3×√6=2√6
(6)4x^2=25
x^2=25/4
x^2=(5/2)^2
x=5/2或x=-5/2