Mathématiques

Question

On peux m'aider sil vous plait ?
Resoudre les équation suivantes
a)x^2-4x=0
b)3x^2-9x=0
c)4x^2=3x
d)x=x^2
e) 3x^2-5=5x^2-5+3x
f)25x^2+10x+1=0
g)9x^2-12x+4=0
h)x^2+2x+1=0
i) 16x^2-8x+1=0


Sil vous plait :) mercii davance :)

1 Réponse

  • a)x²-4x=0 
    x (x -4)
    x = 0  ou x -4 = 0  x = 4   donc solution (0;4)

    b)3x²-9x=0
    3x (x -3) =0
    3x =0  x = 0    ou x-3 = 0  x = 3   donc solution ( 0.3)

    c)4x²=3x
    4x² -3x = 0
    x ( 4x -3) = 0

    x =0   4x-3 =0  4x = 3   x = 3/4   solution ( 0.3/4)


    d)x=x²
    x -x² =0
    x (1-x) =0
    x =0    1-x =0   -x = -1   x = 1    solution (0.1)

    e) 3x²-5=5x²-5+3x
    3x² -5 -5x² +5 -3x =0
    -2x² -3x =0
    x (-2x -3) =0
    x =0   -2x -3 = 0    -2x =3   x = -3/2    solution (0 .  -3/2)

    f)25x²+10x+1=0
    (5x +1) (5x+1) =0
    5x+1 =0  x = -1/5         soltion (-1/5)


     g)9x²-12x+4=0
    (3x -2)(3x-2) =0
    3x-2 =0     x =2/3   solution (2/3)

    h)x²+2x+1=0
    (x+1)(x+1) =0
    x+1 =0
    x =-1      solution (-1)

    i) 16x²-8x+1=0
    (4x -1)(4x-1) = 0
    4x-1 =0
    x = 1/4   solution (1/4)


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