1) (1ц-4/9):(1/3-1/4); 2) ( 5/7-2/3):(4/9-5/12); помогите пожалуйста)))))

(1 - 4/9):(1/3 - 1/4) = 20
9/9 - 4/9 = 5/9
1/3 - 1/4 = 4/12 - 3/12 = 1/12
5/9 : 1/12 = 5/9 * 12/1 = 20

(5/7 - 2/3):(4/9 - 5/12) = 1 5/7
5/7 - 2/3 = 16/21 - 15/21 = 1/21
4/9 - 5/12 = 16/36 - 15/36 = 1/36
1/21 : 1/36 = 1/21 * 36/1 = 12/7 = 1 5/7