【1】原式=(√6-√2)²
=√6²-2×√6×√2+√2²
=6-2×√3×√2×√2+2
=6-2×2×√3+2
=6-4√3+2
=8-4√3
【2】原式=(√8-1)/√2
=√2×(√8-1)/√2²
=(√2×√8-√2)/2
=(√16-√2)/2
=(4-√2)/2
【3】原式=6√5×(1/5)√5
=(6×1/5)×√(5×5)
=6/5 ×5
=6
【4】原式=√5×√12÷√(1/5)
=√(5×12÷1/5)
=√(5×12×5)
=√300
=√100×√3
=10√3