Y=2x³ - 8x² + 8x
y= 2x(x² - 4x +4)
f(y)= 2x(x² - 4x + 4)
2x(x² - 4x + 4)=0
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2x = 0 | x² - 4x + 4 = 0
x₁ = 0 | D= 16 - 16 = 0 (1 корень)
| x₂= (4 +- 0) / 2
| x₂= 2
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y₁=2*0³ - 8*0² + 8*0 = 0
y₂ = 2*2³ - 8*2² + 8*2 = 16 - 32 + 16 = 0