4^2-3^3=16-27=-11
(-2)^3+(-5)^2=-8+25=17
#######
(а+2в)(2а-в)=2а^2-ав+4ав-2в^2=2а^2+3ав-2в^2.
а=3 в=8
2×3^2+3×3×8-2×8^2=18+72-128=90-128=-38
############
х+а×в
#############
2/3 х=-6
2х=-6×3
2х=-18
х=-18:9=-2
######
11.2-4х=0
11.2=4х
х=11.2:4=2.8
################
1.6×(5х-1)=1.8х-4.7
8х-1.6=1.8х-4.7
8х-1.8х=-4.7+1.6
6.2х=-3.1
х=-3.1:6.2=-0.5
$$$$$$$$$$$$$
3.3+1.2х=8.1
1.2х=8.1-3.3
1.2х=4.8
х=4.8:1.2=4