Bonjour aidez moi c urgent

Bonsoir

a = 5/8 - 3/4 = 5/8 - 6/8 = -1/8

b ) (1/3 -5/4) x 4/7
     (4/12 - 15/12) x 4/7
    - 11/12 x 4/7 = - 44/ 84 = -11/21

c) 2/3 - 1/4 x 2/3 + 5/5
2/3 - 1/6 +5/5
20/30 - 5/30 + 30/30 = 45/50 = 9/10

d) (1/3+1/2) : (1/2-1/5)
(2/6 +3/6) : (5/10 - 2/10)
5/6 : 3/10 = 5/6 x 10/3 = 50/18= 25/9

E = 5 x 10⁵
F = 6 x 10⁵ sur 12 x 10⁴ = 0.5 x 10⁻¹ = 5 x 10⁻²

HF/HL = HG/HK = FG/LK
3/5.5 = 5 /LK
3LK = 5.5 x 5
3LK = 27.5
LK = ≈ 9.16 cm

7.5/HL = 5/9.16
5 HL = 7.5 x 9.16
5 HL = 68.7
HL = 13.74

FL = 13.74 - 7.5 = 6.24

A = 3y -15y² -5 + 25y  = -15y² +28y -5
B = -12 +6x - 6x +3x² = 3x² -12