найдите значение выражения а) -2,5-(1 1/3+а) если а=-1/6 б) (-1/8+1/5)-(4,8-4,9)-0,05

а) -2,5 - (1 1/3 + а), если а = -1/6;

-2,5 – (1 1/3 + (-1/6)) = 1 1/6.

1). 1 1/3 + (-1/6) = 4/3 + (-1/6) = (4 * 2) / (3 * 2) + (-1/6) = 8/6 + (-1/6) = (8 - 1) / 6 = 7/6 = 1 1/6.

б) (-1/8 + 1/5) - (4,8 - 4,9) - 0,05 = 1/8.

1). -1/8 + 1/5 = (-1 * 5) / (8 * 5) + (1 * 8) / (5 * 8) = -5/40 + 8/40 = (-5 + 8) / 40 = 3/40;

2). 4,8 – 4,9 = -0,1;

3). 3/40 – (-0,1) = 3/40 + 0,1 = 3/40 + 1/10 = 3/40 + (1 * 4) / (10 * 4) = 3/40 + 4/40 = (3 + 4) / 40 = 7/40;

4). 7/40 – 0,05 = 7/40 – 5/100 = (7 * 5) / (40 * 5) – (5 * 2) / (100 * 2) = 35/200 – 10/200 = (35 - 10) / 200 = 25/200 = 1/8.