2^8*2^1/2:2^12=2^8+1/2:2^12=2^17/2:2^12=2^17/2-12=2^-7/2
1)(х^2+8х)-(4-3х)=х^2+8х-4+3х=х^2+11х-4
2)(2х^2+5х)-(4х^2-2х)=2х^2+5х-4х^2+2х=-2х^2+7х
2+81-45x+8=0
-45x+91=0
-45x=-91
x=2,02
12х-8х+24 больше 6-5х
4х+24 больше 6-5х
7(х-3)=5(х+1)
7х-21=5х+5
7х-5х=5+21
2х=26
х=26÷2
х=13