Математика 6 класс

Упражнение 328

Условие:

Решите уравнение:
а) х + 4/15 = 2/3 + 2/5;        в) у - 5/20 = 5/8 - 3/10;
б) (4/5 - х) + 13/20 = 25/30; г) 2/3 - (7/9 - а ) = 1/3.

 

Ответ:

а) х + 4/15 = 2/3 + 2/5 = 2/3 + 2/5 => x = 2/3 + 2/5 - 4/15 = 10/15 + 6/15 - 4/15 = 12/15 = 4/5;
б) (4/5 - х) + 13/20 = 25/30 = 25/30 => 4/5 + 13/20 - 25/30 = x => x = 48/60 + 39/60 - 50/60 = 37/60;
в) у - 5/20 = 5/8 - 3/10 => y = 5/8 - 3/10 + 3/10 = 25/40 - 2/40 + 10/40 = 23/40;
г) 2/3 - (7/9 - а ) = 1/3 => 2/3 - 7/9 + a = 1/3; а = 1/3 - 2/3 + 7/9 = 3/9 -6/9 + 7/9 = 4/9.