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rezolvati in R ecuatia (x+1)(x-1)-(3x+2)=-5+(x-3)2

Răspuns :

(x + 1)(x - 1) - (3x + 2) = - 5 + (x - 3)²
x² - x + x - 1 - 3x - 2 = - 5 + x² - 6x + 9
x² - x² - 3x + 6x = 3 - 5 + 9
3x = 7
x = 7/3
trebuie sa desfacem parantezele:
fol formula (a-b)(a+b)=a²-b²

x²-1-3x-2=5+2x-6
treci neconoscutele intr-o singura parte:
x²-3x-2x=3-1
x²-5x=2
x²-5x-2=0 ---ecuatie de gradul II
Δ=25-8=17
x1=(5+√17)/2
x2=(5-√17)/2