Résoudre les équations 3 (2x-5)=5- (3x-7) -3(2x-4)=5x+3(rac.carr)7 (-4x-3)(5x+2)=0 (2x-3)(4+7x)+(2.... Pergunta de ideia deEmeline200154

Emeline200154 @Emeline200154

May 2019 1 61 Report

Résoudre les équations
3 (2x-5)=5- (3x-7)
-3(2x-4)=5x+3(rac.carr)7

(-4x-3)(5x+2)=0
(2x-3)(4+7x)+(2x-3)(x+4)=0
3x(carré)-2x=7x
(5x-7)(-3x+2)=(-3x+2)(2x-5)
X(carré)=25
X(carré)+4x=-4

Merci bcp

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Commentaires Bonsoir,

3(2x - 5) = 5 - (3x - 7)
6x - 15 = 5 - 3x + 7
6x - 15 = 12 - 3x
6x + 3x = 12 + 15
9x = 27
x = 3

-3(2x - 4) = 5x + 3√7
-6x + 12 = 5x + 3√7
-6x - 5x = 3√7
-11x = 3√7 - 12
x = 3√7 / 11 + 12/11
x ≈ 0.36

(-4x - 3)(4 + 7x) + (2x - 3)(x + 4) = 0
-16x - 28x² - 12 - 21x + 2x² + 8x - 3x - 12 = 0
-32x - 26x² - 24 = 0
-26x² - 32x - 24 = 0
-2(13x² + 16x + 12) = 0
13x² + 16x + 12 = 0
x = $\frac{-16+ \sqrt{16^2-4*13*12} }{2*13}$
x = $\frac{-16+ \sqrt{256-624} }{26}$
x = $\frac{-16+ \sqrt{-368} }{26}$
x ∉ R

Je vous laisse la suite.

3 votes Thanks 2

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