Question

помогите решить 77,78,79

Answer 1

77)
$8 frac{1}{2} - 3 frac{1}{2} div (2 frac{1}{2} + 1 frac{3}{4} ) times 2 frac{3}{7} = frac{17}{2} - frac{7}{2} div ( frac{5}{2} + frac{7}{4} ) times frac{17}{7} = frac{17}{2} - frac{7}{2} div ( frac{10}{4} + frac{7}{4} ) times frac{17}{7} = frac{17}{2} - frac{7}{2} div frac{17}{4} times frac{17}{7} = frac{17}{2} - frac{7}{2} times frac{4}{17} times frac{17}{7} = frac{17}{2} - 2 = frac{17}{2} - frac{4}{2} = frac{13}{2} = 6 frac{1}{2}$
78)
$9 frac{2}{7} + 1 frac{7}{9} div (2 frac{2}{5} - 1 frac{1}{3} ) times frac{3}{7} = frac{65}{7} + frac{16}{9} div ( frac{12}{5} - frac{4}{3} ) times frac{3}{7} = frac{65}{7} + frac{16}{9} div ( frac{36}{15} - frac{20}{15} ) times frac{3}{7} = frac{65}{7} + frac{16}{9} div frac{16}{15} times frac{3}{7} = frac{65}{7} + frac{16}{9} times frac{15}{16} times frac{3}{7} = frac{65}{7} + frac{5}{7} = frac{70}{7} = 10$
79)
$4 frac{1}{6} + (2 frac{3}{4} - 2 frac{1}{6} ) div 2 frac{4}{5} - 1 frac{3}{8} = frac{25}{6} + ( frac{11}{4} - frac{13}{6} ) div frac{14}{5} - frac{11}{8} = frac{25}{6} + ( frac{33}{12} - frac{26}{12} ) div frac{14}{5} - frac{11}{8} = frac{25}{6} + frac{7}{12} times frac{5}{14} - frac{11}{8} = frac{25}{6} + frac{5}{24} - frac{11}{8} = frac{100}{24} + frac{5}{24} - frac{33}{24} = frac{72}{24} = 3$

Answer 2

77. 17/2-7/2:(5/2+7/4)*17/7= 17/2-7/2:17/4*17/7=17/2-7/2*4/17*17/7=17/2-2=13/2=6,5
78. 65/7+16/9:(12/5-4/3)*3/7=65/7+16/9*15/16*3/7=65/7+15/21=210/21=10
79. 25/6+(11/4-13/6):14/5-11/8=26/6+14/24*5/14-11/8=25/6+5/24-11/8=72/24=3