3)<span>(х + 4)^2 - х^2 = 2х + 1
х</span>^2+8х+16-х^2 -2х-1=0
8х-2х= -16+1
6х= -15
х= -15/6
<span>4) х (х^2 - 2) = х^3 +8
</span>х^3-2х=х^3 +8
х^3-2х-х^3 -8=0
-2х=8
х= -4
4m³ - 32c³=4(m³ - 8c³)=4(m³ - (2c)³)=4(m-2c)(m²+2mc+4c²)
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Смотри.......................
150с×5=750с=6 мин 30 с
150мин÷5=30мин