👤

bonsoir j'aimerai que queleq'un me resoudre ces equations merci beaucoup

1) 4x au carre-28x+49=0

2) 3x au carre-2x+5=0

3) x au carre -10x+24=0

4) x au carre+5x-14=0

5) x au carre-3x+2=0



Répondre :

1) 4x^2 - 28x + 49 = 0

Delta^2 = (-28)^2-4*4*49
Delta^2 = 784 - 784
Delta^2 = 0
Delta = 0 donc une solution

X1 = 28/(2*4)
X1 = 28/8
X1 = 7/2

2) 3x^2 - 2x + 5 = 0

Delta^2 = (-2)^2 - 4*3*5
Delta^2 = 4 - 60
Delta^2 = (-56)
Delta^2 < 0 impossible donc pas de solution pour cette équation

3) x^2 - 10x + 24 = 0

Delta^2 = (-10)^2 - 4*1*24
Delta^2 = 100 - 96
Delta^2 = 4
Delta = V4
Delta = 2 > 0 donc 2 solutions

X1 = (10-2)/2
X1 = 8/2
X1 = 4

X2 = (10+2)/2
X2 = 12/2
X2 = 6

4) x^2 + 5x - 14 = 0

Delta^2 = 5^2 - 4*1*(-14)
Delta^2 = 25 + 56
Delta^2 = 81
Delta = V81
Delta = 9 > 0 donc 2 solutions

X1 = (-5-9)/2
X1 = (-14)/2
X1 = (-7)

X2 = (-5+9)/2
X2 = 4/2
X2 = 2

5) x^2 - 3x + 2 = 0

Delta^2 = (-3)^2 - 4*1*2
Delta^2 = 9 - 8
Delta^2 = 1
Delta = V1
Delta = 1 > 0 donc 2 solutions

X1 = (3-1)/2
X1 = 2/2
X1 = 1

X2 = (3+1)/2
X2 = 4/2
X2 = 2