Réponse :
Explications étape par étape
3x + 4 = 2
⇔ 3x = 2 - 4
⇔ 3x = -2
⇔ x = -2/3
16x - 2x + 3 = -2x
⇔ 16x - 2x + 2x = -3
⇔ 16x = -3
⇔ x = -3/16
2x + 1 + 54x = 23x + 2
⇔ 2x + 54x - 23x = 2 - 1
⇔ 33x = 1
⇔ x = 1/33
1x + 81 = 8
⇔ x = 8 - 81
⇔ x = -73
17x + 3 * 1x - 71 + 2x1 = 12x1
⇔ 17x + 3x - 71 + 2 = 12
⇔ 20x = 12 - 2 + 71
⇔ 20x = 81
⇔ x = 81/20
(8x+3) (3x-2) = 2(x-2)
⇔ 24x² - 16x + 9x - 6 = 2x - 4
⇔ 24x² - 16x + 9x - 2x = -4 + 6
⇔ 24x² - 9x = 2
⇔ 24x² - 9x - 2 = 0
∆ = b² - 4ac = (-9)² - 4 · 24 · (-2) = 81 + 192 = 273
Δ>0
x₁ = 9 - √273 / 2 · 24 ≅ -0.15672
x₂ = 9 + √273 / 2 · 24 ≅ 0.53172
1 / x + 7 = 0
⇔ 1/x = -7
⇔ 1 = - 7x
⇔ x = - 1/7
( x + 1 ) * 7 / ( x - 3 ) = ( x + 1 ) * x
⇔ [ ( x + 1 ) * 7 / ( x - 3 ) ] * ( x - 3 ) = ( x + 1 ) * x * ( x - 3 )
⇔ 7 ( x + 1 ) = ( x + 1 ) * x * ( x - 3 ) simplification par (x+1)
⇔ 7 = x * ( x - 3 )
⇔ 7 = x² - 3x
⇔ x² - 3x - 7 = 0
∆ = b² - 4 ac = (-3)² - 4· 1· (-7) = 9 + 28 = 37
Δ>0
x₁ = 3 - √37/ 2·1 ≅ -1.5414
x₂ = 3 + √37 / 2.1 ≅ 4.5414
