Раскрываем скобки
7,2к-25,92=19,44
7,2к=19,44+25,92
7,2к=45,36
к=45,36/7,2
к=6,3
3.2(х-1.36)=6.496
3.2х-4.352=6.496
3.2х=6.496+4.352
3.2х=10.848
х=10.848:3.2
х=3.39
(5.6+3.7)*2=4.65 ................
<span>80*b-3*90+430=1600/2</span>
<span>80b=800-430+270</span>
<span>80b=640</span>
<span>b=8</span>