20. Ділення дробів - 21. Знаходження дробу » 889

Обчисли значення виразу. а) (0,5 ∶ 1/3 - 2/3 ∶ 4/9 + 3/(8 ) • 4)/(1/5 ∶ 2/5 + 1/(4 ) ∶ 0,25) = (1/2 ∶ 1/3 - 2/3 ∶ 4/9 + 3/(8 ) • 4)/(1/5 ∶ 2/5 + 1/(4 ) ∶ 1/4) = (1/2 • 3/1 - 2/3 • 9/4 + 3/(2 ))/(1/5 • 5/2 + 1/(4 ) • 4/1) = (3/2 - 3/2 + 3/(2 ))/(1/2 + 1/(1 )) = (3/2)/(3/2) = 3/2 • 2/3 = 1. б) (3/5 ∶ 〖(3/5)〗^2+ 1,6 - 2/(3 ) ∶ 2 1/(2 ))/(〖(2/3)〗^2 ∶ 5/6 - 2/(3 ) • 0,2 + 3/(5 )) = (3/5 ∶ 9/25 + 1 3/5 - 2/(3 ) ∶ 5/(2 ))/(4/9 ∶ 5/6 - 2/(3 ) • 1/5 + 3/(5 )) = (3/5 • 25/9 + 8/5 - 2/(3 ) • 2/(5 ))/(4/9 • 6/5 - 2/(15 ) + 3/(5 )) = (5/3 + 8/5 - 4/(15 ))/(8/15 - 2/(15 ) + 3/(5 )) = (25/15 + 24/15 - 4/(15 ))/(2/(5 ) + 3/(5 )) = 3/1 = 3.