Вопрос от посетителя:
Решите уравнения
а)5x+(3x-7)=9;
б)3y-(5-y)=11;
в)48=11-(9a+2);
г)13-(5x+11)=6x;
Илюха отвечает:
а) 5x + (3x – 7) = 9,
5х + 3х – 7 = 9,
8х – 7 = 9,
8х = 9 + 7,
8х = 16,
х = 16 : 8,
х = 2;
б) 3y – (5 – y) = 11,
3у – 5 + у = 11,
4у – 5 = 11,
4у = 11 + 5,
4у = 16,
у = 16 : 4,
у = 4;
в) 48 = 11 – (9a + 2),
48 = 11 – 9а – 2,
48 = 9 – 9а,
9а = 9 – 48,
9а = – 39,
а = -39/9 = -13/3 = – 4 целые 1/3;
г) 13 – (5x + 11) = 6x,
13 – 5х – 11 = 6х,
2 – 5х = 6х,
-5х – 6х = -2,
-11х = -2,
х = 2/11.