4x* + 25 = -20x
x* = 8
Equation produit

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Grade: Education Subject: mathematiques
4x* + 25 = -20x
x* = 8
Equation produit
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Answer (51)

Best Answer
(177)
4x²+20x+25 = 0  = a²+2ab+b² = (a+b)² = 0

(2x+5)² = 0

2x+5 = 0
2x = -5
x = -5/2

x² = 8

x= -2V2
x =2V2


(320)
Bonjour 
4x²+25 = 20x revient à 
4x² + 20x + 25 = 0
(2x + 5)² = 0    
2x+5 = 0 
x = -5/2 

x² = 8 
x² - 8 = 0        forme de a² - b² = (a-b)(a+b) 
(x - √8)(x+√8) = 0   
deux solutions soit 
x = √8 = 2√2 
soit
x = -√8 = -2√2
Bonne journée