1. а) 1/4 - 0.2 = 0.25 - 0.2 = 0.05
б) -3/7 + 0.2 = -3/7 + 1/5 = -15/35 + 7/35 = -8/35
в) -1/3 * 1.5 = -1/3 * 1 1/2 = -1/3 * 3/2 = -3/6 = -1/2
г) 0.36 / (-18/19) = -(36/100 * 19/18) = -38/100 = -0.38
2. а) -3 1/2 + 2.3 = -3.5 + 2.3 = -1.2
б) 2 1/3 - 4.1 = 2.33 - 4.1 = -1.77
в) 2 3/4 * (-1.6) = -(11/4 * 16/10) = -44/10 = -4.4
г) -6.25 / 1 1/4 = -6 1/4 * 4/5 = -(25/4 * 4/5) = -25/5 = -5
960:0,8=9600:8=1200 всего птиц на ферме...
a=8,b=4 т,к 8/2=4
Pпр=(a+b)*2=(8+4)*2=12*2=24
P = 2 (а+b) = 2a+2b
36 = 2*8 + 2*b
2b = 36-16
2b=20
b=20/2
b=10 см - длина
проверим
2(8+10) = 36
2*18 = 36
36=36