20x - 4 - 25x² = - 25x² + 20x - 4
-25x² + 20x - 4
rezolvam ecuatia de gradul II
Δ = b² - 4ac
Δ=400 - 4×(-4)×)(-25)
Δ=400 - 400
x=(-b+√Δ)2a
x₁ = x₂= x = - b/2a
x₁ = x₂= x = - b/2a=-20/2×(-25)=2/5
x =2/5
descompunere:a(x-x₁)(x-x₂)
20x - 4 - 25x² = 25(x - 2/5)(x - 2/5) = (5x - 2)²