[tex]2 \frac{1}{3} * 3,5 = 3 \frac{1}{3} * x[/tex]

2 1/3 * 3,5 = 3 1/3 * х7/3 * 7/2 = 10/3 * х49/6 = 10/3 * хх = 49/6 : 10/3х = 49/6 * 3/10 = (49*1)/(2*10) = 49/20х = 2 целых 9/20----------------------------Проверка:7/3 * 7/2 = 10/3 * 49/2049/6 = 490/608,1(6) = 8,1(6)Пояснения:2 1/3 = (2*3+1)/3 = 7/33,5 = 3 5/10 = 3 1/2 = (3*2+1)/2 = 7/23 1/3 = (3*3+1)/3 = 10/3