А) (2 3/8 -х): 3 1/4+ 2 13/15= 3 1/6 б) 4 1/2-5 - вопрос №407371123831421315316412513201423156 от koteleva 02.07.2020 23:56

Question

Математика: А) (2 3/8 -х): 3 1/4+ 2 13/15= 3 1/6 б) 4 1/2-5 1/3: (20х-14 2/3)=1 5/6 ! 2 3/8-2целые три восьмых

koteleva · Answer

А) (2 3/8 -х) / 3 1/4 + 2 13/15 = 3 1/6
      (19/8 - х) / 13/4 + 43/15 = 19/6       19/26 - 4/13 *х + 43/15 = 19/6
      19/26 +43/15 -19/6 = 4/13* х       285/390 + 598/390 - 1235/390 =4/13 * х
      -352/390 = 4/13 *х       х = -44/15 = -2 14/15
Б) 4 1/2 - 5 1/3 / (20х -14 2/3) = 1 5/6       9/2 -16/3 / (20х -44/3) = 11/6
     16/3 / (20х -44/3) = 11/6 - 9/2      16/3 / (20х -44/3) = - 16/6       , разделим правую и левую часть уравнения на 16/6        2 /(20х - 44 /3)  = -1       2 = -20х +44/3
20х = 44/3 -2        20х =44/3 - 6/3       20х = 38/3       60х = 38   х =  38/60     х = 19/30