8 9/20 * 2/13=169/20 * 2/13=13/10=1 3/10
5 1/3 * 3/8=16/3 * 3/8=2
10 1/2 * 2/7=21/2 * 2/7=3
5/6 * 1 6/5=5/6 * 11/5=11/6=1 5/6
3 1/9 * 3/8=28/9 * 3/8=14/12=7/6=1 1/6
9 1/7 * 3/4=64/7 * 3/4=48/7=6 6/7
10 1/5 * 10/17=51/5 * 10/17=3*2=6
3/11 * 5 1/2=3/11 * 11/2=3/2=1 1/2
X+x+5=29
2x+5=29
2x=29-5
2x=24
x=24:2
x=12
Ответ:12
(0,8 × 7 + 0,64) · (1,25 × 7 - 4/5 × 1,25) + 31,64) = (5,6+0,64) × (8,75-10) + 31,64 = 6,24 × (-1,25) + 31,64 = -7,8 + 31,64=23,84
А)Длинна окружности(С)=2*П*R(радиус)=2*3,14*5=31,4см
С=2*3,14*2,5=7,85м
Б)С=2*3*7,5=45см
<span>С=2*3*5=30м</span>