(5×1/3 - 3×3/4) ÷ ( 1×2/3 + 2×1/4) = (16/3 -15/4) ÷ (5/3 + 9/4) = (64/12 - 45/12) ÷ (20/12 + 27/12) = 19/12 ÷ 47/12 = 19/12 × 12/47 = 19/47 (т.к. 12 и 12 сокращаются)
ответ: 19/47.
