1. 解方程:
(1) $11x + 64 - 2x = 100 - 9x$;
(2) $3(3 - 5x) - 4(5 + 2x) = 6(1 - 3x) - 12$;
(3) $\frac{x + 1}{4} - 1 = \frac{2x - 1}{6}$;
(4) $\frac{3y - 6}{4} = 1 - \frac{5y - 7}{3}$;
(5) $\frac{8}{3}(x - \frac{3}{4}) + \frac{5}{2} = 2(x - \frac{3}{4})$;
(6) $1 - \frac{x - 3}{2} = \frac{x - 2}{3} - \frac{x - 1}{6}$.

(1)x=2
(2)x=-1
(3)x=-7
(4)y=2
(5)x=-3
(6)$x=\frac{9}{2}$

2. 解方程:
(1)$\dfrac{0.1 - 2x}{0.3}=1+\dfrac{x}{0.15};$
(2)$\dfrac{0.4x + 0.9}{0.5}-\dfrac{0.03 + 0.02x}{0.03}=\dfrac{x - 5}{2}.$

(1)x=-0.05
(2)方程整理得$\frac{4x+9}{5}-\frac{3+2x}{3}=\frac{x-5}{2}$,解得x=9.

3. $\frac{x}{1×2}+\frac{x}{2×3}+\frac{x}{3×4}+\dots+\frac{x}{85×86}=5÷\frac{1}{4^2 + 1}$

原式$= (1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\dots+\frac{1}{85}-\frac{1}{86})x = 85$,
所以$(1-\frac{1}{86})x = 85$,解得x=86.