2.214 Вычислите значение выражения: a) (12$$\frac{1}{3}$$-11$$\frac{1}{4}$$)+(14-9$$\frac{8}{15}$$); б) (15-12$$\frac{5}{8}$$) - (13$$\frac{1}{2}$$-11$$\frac{2}{9}$$); в) (14$$\frac{2}{3}$$-5$$\frac{5}{9}$$)-($$3\frac{7}{8}$$+4$$\frac{5}{6}$$)+(10$$\frac{3}{4}$$-4$$\frac{4}{9}$$); г) (14$$\frac{5}{7}$$-14)+(30-29$$\frac{5}{7}$$)+($$3\frac{1}{7}$$-$$\frac{23}{28}$$) 2.215 Вычислите: a) 2$$\frac{3}{4}$$ + 3,4; б) 4$$\frac{7}{25}$$ - 3,3; в) 7,2 - 6$$\frac{5}{6}$$; г) 5$$\frac{7}{12}$$ - 1,6. 2.216 Найдите корень уравнения: a) x + 3$$\frac{8}{13}$$ = 6; в) a - 7$$\frac{5}{8}$$ = $$\frac{7}{12}$$; д) 5$$\frac{25}{36}$$ - t = 1$$\frac{1}{12}$$ + 2$$\frac{3}{8}$$; б) 14$$\frac{4}{9}$$ + y = 23; г) 12$$\frac{1}{6}$$ - b = 4$$\frac{8}{15}$$; е) $$\frac{4}{7}$$ - $$\frac{1}{3}$$ + z = $$\frac{13}{14}$$ - $$\frac{7}{8}$$.

2.214 а) (12$$\frac{1}{3}$$-11$$\frac{1}{4}$$)+(14-9$$\frac{8}{15}$$) $$12\frac{1}{3} - 11\frac{1}{4} = \frac{37}{3} - \frac{45}{4} = \frac{148-135}{12} = \frac{13}{12}$$ $$14-9\frac{8}{15} = \frac{210}{15} - \frac{143}{15} = \frac{67}{15}$$ $$\frac{13}{12} + \frac{67}{15} = \frac{65+268}{60} = \frac{333}{60} = \frac{111}{20} = 5\frac{11}{20}$$ б) (15-12$$\frac{5}{8}$$) - (13$$\frac{1}{2}$$-11$$\frac{2}{9}$$) $$15-12\frac{5}{8} = \frac{120}{8} - \frac{101}{8} = \frac{19}{8}$$ $$13\frac{1}{2} - 11\frac{2}{9} = \frac{27}{2} - \frac{101}{9} = \frac{243-202}{18} = \frac{41}{18}$$ $$\frac{19}{8} - \frac{41}{18} = \frac{171-164}{72} = \frac{7}{72}$$ в) (14$$\frac{2}{3}$$-5$$\frac{5}{9}$$)-($$3\frac{7}{8}$$+4$$\frac{5}{6}$$)+(10$$\frac{3}{4}$$-4$$\frac{4}{9}$$) $$14\frac{2}{3} - 5\frac{5}{9} = \frac{44}{3} - \frac{50}{9} = \frac{132-50}{9} = \frac{82}{9}$$ $$3\frac{7}{8} + 4\frac{5}{6} = \frac{31}{8} + \frac{29}{6} = \frac{93+116}{24} = \frac{209}{24}$$ $$10\frac{3}{4} - 4\frac{4}{9} = \frac{43}{4} - \frac{40}{9} = \frac{387-160}{36} = \frac{227}{36}$$ $$\frac{82}{9} - \frac{209}{24} + \frac{227}{36} = \frac{656-627+227}{72} = \frac{256}{72} = \frac{32}{9} = 3\frac{5}{9}$$ г) (14$$\frac{5}{7}$$-14)+(30-29$$\frac{5}{7}$$)+($$3\frac{1}{7}$$-$$\frac{23}{28}$$) $$14\frac{5}{7} - 14 = \frac{5}{7}$$ $$30 - 29\frac{5}{7} = \frac{2}{7}$$ $$3\frac{1}{7} - \frac{23}{28} = \frac{22}{7} - \frac{23}{28} = \frac{88-23}{28} = \frac{65}{28}$$ $$\frac{5}{7} + \frac{2}{7} + \frac{65}{28} = \frac{20+8+65}{28} = \frac{93}{28} = 3\frac{9}{28}$$ 2.215 а) 2$$\frac{3}{4}$$ + 3,4 $$2\frac{3}{4} + 3,4 = 2,75 + 3,4 = 6,15$$ б) 4$$\frac{7}{25}$$ - 3,3 $$4\frac{7}{25} - 3,3 = 4,28 - 3,3 = 0,98$$ в) 7,2 - 6$$\frac{5}{6}$$ $$7,2 - 6\frac{5}{6} = 7,2 - 6,8333... = 0,3666... = \frac{11}{30}$$ г) 5$$\frac{7}{12}$$ - 1,6 $$5\frac{7}{12} - 1,6 = 5,5833... - 1,6 = 3,9833... = 3\frac{59}{60}$$ 2.216 а) x + 3$$\frac{8}{13}$$ = 6 $$x = 6 - 3\frac{8}{13} = \frac{78}{13} - \frac{47}{13} = \frac{31}{13} = 2\frac{5}{13}$$ б) 14$$\frac{4}{9}$$ + y = 23 $$y = 23 - 14\frac{4}{9} = \frac{207}{9} - \frac{130}{9} = \frac{77}{9} = 8\frac{5}{9}$$ в) a - 7$$\frac{5}{8}$$ = $$\frac{7}{12}$$ $$a = \frac{7}{12} + 7\frac{5}{8} = \frac{14+171}{24} = \frac{185}{24} = 7\frac{17}{24}$$ г) 12$$\frac{1}{6}$$ - b = 4$$\frac{8}{15}$$ $$b = 12\frac{1}{6} - 4\frac{8}{15} = \frac{73}{6} - \frac{68}{15} = \frac{365-136}{30} = \frac{229}{30} = 7\frac{19}{30}$$ д) 5$$\frac{25}{36}$$ - t = 1$$\frac{1}{12}$$ + 2$$\frac{3}{8}$$ $$1\frac{1}{12} + 2\frac{3}{8} = \frac{13}{12} + \frac{19}{8} = \frac{26+57}{24} = \frac{83}{24}$$ $$t = 5\frac{25}{36} - \frac{83}{24} = \frac{205}{36} - \frac{83}{24} = \frac{410-249}{72} = \frac{161}{72} = 2\frac{17}{72}$$ е) $$\frac{4}{7}$$ - $$\frac{1}{3}$$ + z = $$\frac{13}{14}$$ - $$\frac{7}{8}$$ $$\frac{4}{7} - \frac{1}{3} = \frac{12-7}{21} = \frac{5}{21}$$ $$\frac{13}{14} - \frac{7}{8} = \frac{52-49}{56} = \frac{3}{56}$$ $$z = \frac{3}{56} - \frac{5}{21} = \frac{9-40}{168} = -\frac{31}{168}$$