Х+(х-3)=19
х+х-3=19
2х-3=19
х=19+3
х=22
х=22:2
х=11
2/3:4/9х-4/9+1/20=4/5
(4/9х-4/9+1/20)4/5=2/3
((4/9)х-4/9+1/20)2/5=1/3
(8/45)х-8/45+1/50=4/5
(8/45)х=8/45-1/50+4/5
(8/45)х=(400-45+450)/2250
(8/45)х=905/2250
х=(905/2250)*45/8
x=2,2625
1.)
45000:n=90
n=45000:90
n=500
2.)
n×80=4800
n=4800:80
n=60
3.)
2000:n=5
n=2000:5
n=400