Найдите значение выражения 0.8 (3x-14) - 0.3 (4-5x) при x=3 цел. 1/13

0,8 * (3 * x - 14) - 0,3 * (4 - 5 * x) при x = 3 1/13.

0,8 * (3 * 3 1/13 - 14) - 0,3 * (4 - 5 * 3 1/13) = - 2/65.

1). 3 * 3 1/13 = 3 * 40/13 = 120/13 = 9 3/13;

2). 9 3/13 - 14 = 9 3/13 - 13 13/13 = - 4 10/13;

3). 5 * 3 1/13 = 5 * 40/13 = 200/13 = 15 5/13;

4). 4 - 15 5/13 = 3 13/13 - 15 5/13 = - 12 8/13;

5). 0,8 * (-4 10/13) = 8/10 * (-62/13) = - (8 * 62) / (10 * 13) = - 496/130;

6). 0,3 * (-12 8/13) = 3/10 * (-164/13) = - (3 * 164) / (10 * 13) = - 492/130;

7). - 496/130 - (-492/130) = - 496/130 + 492/130 = - 4/130 = - 2/65.