А) (20+7)(20+7) = (20+7)2 = 20*20+20*7+7*20+7*7 = 729
А×2=40×4
а×2=160
а=160:2
а=80
\*2 \*5
в) 5 13/35 + 2 13/14= 7 (13*2 + 13*5)/ 70= 7 (26+65)/70= 7 91/70= 8 21/70 = 8 3/10= 8.3
\*2 \*3
г) 5 5/33 - 4 7/22= 1 (5*2- 7*3)/66 = 1 (10-21)/66= (76-21)/66= 55/66= 5/6
Ответы: в) 8.3 г) 5/6
565.
21/25 * 5/7 - 3/16 * 4/15=3/5 - 1/20=12/20-1/20=11/20
5 5/12 * 4/13 - 2 5/8 * 3/14=65/12 * 4/13 - 21/8 * 3/14=5/3 - 9/16=80/48 - 27/48=53/48=1 5/48
15 2/5 * 1 5/7+6 10/27 * 3 3/8=77/5 * 12/7 + 172/27 * 27/8=26 2/5+21 1/2=26 4/10+21 5/10=47 9/10
15 4/7 - 4 3/8*(1 3/7 - 34/35)=15 4/7 - 4 3/8*(1 15/35 - 34/35)=15 4/7 - 35/8 * 16/35=15 4/7 - 2=13 4/7
(3/4)^3=27/64
(5/6)^2=25/36
.
568 де.
(2 3/4 +4 1/8) * 1 5/11=(2 6/8 + 4 1/8) * 16/11=6 7/8 * 16/11=55/8 * 16/11=10
1 2/5 * (1 1/14 - 5/7)=7/5 *(15/14 - 10/14)=7/5 * 5/14=1/2