一、解方程。
38.1 - x = 17.6 3.9 - 2.4 + 6x = 10.5 3.5x + 4.7x = 164
3.81 + 0.5x = 6.4 0.48x - 7.49 = 9.79 (0.97 + 4.23)x = 1.872
2.5x - x = 1.8 9(x - 1.1) = 18.9 6x + 2×2.5 = 41
x - $\frac{2}{5}=\frac{3}{10}$ x + $\frac{1}{5}+\frac{4}{5}=10$ $\frac{1}{12}+x+\frac{1}{3}=\frac{1}{2}$
x - $\frac{6}{7}+\frac{1}{2}=\frac{5}{8}$ x + $\frac{2}{7}-\frac{1}{3}=\frac{3}{5}$ $\frac{1}{2}-\frac{1}{5}+x=\frac{14}{15}$

x = 20.5
x = 1.5
x = 20
x = 5.18
x = 36
x = 0.36
x = 1.2
x = 3.2
x = 6
x = $\frac{7}{10}$
x = 9
x = $\frac{1}{12}$
x = $\frac{55}{56}$
x = $\frac{68}{105}$
x = $\frac{19}{30}$

二、计算下面各题，怎样简便就怎样计算。
15.68÷0.25÷4 $\frac{8}{15}-\frac{1}{6}+\frac{3}{10}$ 2.16÷[15×(4.53 - 4.35)]
27.5×3.7 - 7.5×3.7 $\frac{11}{8}-(\frac{5}{12}-\frac{1}{4})+\frac{5}{8}$ 8.49 + (4.64 - 2.14)×0.64
13.7×0.5 - 3.7÷2 10 - $\frac{7}{12}-\frac{5}{12}-\frac{3}{8}$ 16.2 - (66.7÷23 + 5.14)
(1 - 0.4)×(4.12 + 0.9) $\frac{19}{20}+(\frac{6}{5}-\frac{7}{40})-\frac{7}{10}$ 2.6 + (11.5 - 10.7)÷0.64
1.9×[5.2 - (9 - 7.3)] $\frac{1}{7}+\frac{7}{12}+\frac{6}{7}+\frac{5}{12}$ 4.9÷[2.6 - (12.78 - 10.88)]

15.68 $\frac{2}{3}$ 0.8
74 $1\frac{5}{6}$ 10.09
5 $8\frac{5}{8}$ 8.16
3.012 $\frac{51}{40}$ 3.85
6.65 2 7