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.