bonsoir

exercice 1

Si l'arbre est perpendiculaire au sol, on peut appliquer le théorème de Pythagore.

On a donc : 10² = 7²+h²

100 = 49+h²

h² = 100-49

h = 51

donc h = √51 ≈ 7,1 m

exercice 2

a = -4 b = 3 c = 2 d = -6

(-b) x c | a^2 | (-c) x b ?

d^2 | a x b | c^2

a x (-c) | b^2 | -a x d

(-b) x c = (-3) x (-6) = 18

a^2 = (-4)^2 = 16

(-c) x b = -2 x 3 = -6

d^2 = (-6)^2 = 36

a x b = -4 x 3 = -12

c^2 = 2^2 = 4

a x (-c) = -4 x -2 = 8

b^2 = 3^2 = 9

-a x d = 4 x -6 = -24

Total : -1728

bonne soirée