原式=1/3 ×√0.81 -2×√(6又1/4) +1/10 ×√(8²+6²)
=1/3 × √(81/100) -2×√(25/4) +1/10×√100
=1/3 ×9/10 -2×5/2 +1/10 ×10
=3/10 -5 +1
= -37/10