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a fost răspuns

a)(3-x)(1+2x)=2+4x
b)x^2-(x-2)^2=7x
c)-5x^2+3x+2=0
urgeeeeeent....ajutooooooor

Răspuns :

a) 3 + 6x - x - 2x² = 2 + 4x
- 2x² + x + 1 = 0
Δ = 1 + 8 = 9
x1 = (-1 + 3)/2 = 1
x2 = (-1 - 3)/2 = -2

b) x² - (x² -4x + 4) = 7x
x² - x² + 4x - 4 - 7x = 0
-3x - 4 = 0
x = -4/3

c) -5x² + 3x + 2 = 0
Δ = 9 + 4 × 5 × 2 = 9 + 40 = 49
x1 = (-3 + 7)/6 = 4/6 = 2/3
x2 = (-3 -7)/6 = -10/6 = -5/3 

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