Giải các phương trình sau
a) 5 - ( x - 6 ) - 4 ( 3 - 2x)
b) 3 - 4x (25 - 2x) - 8 $x^{2}$ + x - 300
c) $\frac{5x + 2 }{6}$ - $\frac{8x - 1 }{3}$ = $\frac{4x + 2}{5}$ - 5
d) $\frac{3x + 2}{2}$ - $\frac{3x + 1}{6}$ = 2x + $\frac{5}{3}$
e) x - $\frac{2x + 2}{5}$ + $\frac{x + 8}{6}$ = 7 + $\frac{x - 1}{3}$
f) $\frac{2( x - 3)}{7}$ - x + 2 - $\frac{13x + 4}{21}$