а) - ( - ) * ( + )

1. - = = =

2. + = = =

3. * = =

4. - = ==

б) (2/3 + 7/8 - 5/6) * (1-5/17)

1. 2/3 + 7/8 - 5/6 = 16+21-20/24 = 17/24

2. 1 - 5/17 = 17/17-5/17 = 12/17

3. 17/24 * 12/17 = 1/2

в) (2 1/2)^2 *8/15 - 5/9

1. (2 1/2)^2 = (5/2)^2 =5^2/2^2=25/4

2. 25/4 * 8/15 = 25*8/4*15 = 10/3

3. 10/3 - 5/9 = 30-5/9 = 25/9 = 2 7/9

г) (2 1/3 * 1 2/7)^3 * 2/9

1. (2 1/3 * 1 2/7)^3 =  7^3/3^3 * 9^3/7^3 = 343/27 * 729/343 = 27

2. 27 * 2/9 = 27*2 / 1*9 = 6

д) (3 1/14 - 2 5/21) * (2,7-2,1)

1. (3 1/14 - 2 5/21) = 43/14 - 47/21 = 129 - 94/42 = 35/42 = 5/6

2. 2.7 - 2.1 = 0.6 = 6/10 = 3/5

3. 5/6 * 3/5 = 1/2

е) (4 13/18 - 3 7/9) * (1/2 - 4/17)

1. 4 13/18 - 3 7/9 = 85/18 - 34/9 = 85-68/18 = 17/18

2. 1/2 - 4/17 = 17 - 8/ 34 = 9/34

3. 17/18 * 9/34 = 1/4

ж) 7/11 * ((3/7)^2 + 5/7)

1. (3/7)^2 = 3^2/7^2= 9/49

2. 9/49 + 5/7 = 9 + 35/49 = 44/49

3. 7/11 * 44/49 = 4/7

з) (7/12 - 3/16 - 5/24) + (1/4)^2

1. (7/12 - 3/16 - 5/24) = 28-9+10/48 = 29/48

2. (1/4)^2 = 1^2/4^2 = 1/16

3. 29/48 + 1/16 = 29+ 3 /48 = 32/48 =  2/3