bonjour
AB = ( 1 - 3 )² + ( 1 - 5 )² = ( - 2)² + ( - 4)² = 4 + 16 = 20
BC = ( 7 - 1)² + ( - 2 - 1 )² = 6² + ( - 3)² = 36 + 9 = 45
CD = ( 9 - 7 )² + ( 2 + 2 )² = 2² + 4 ² = 4 + 16 = 20
AD = ( 9 - 3 )² + ( 2 - 5 )² = 6 ² + ( - 3 )² = 36 + 9 = 45
AB = CD et BC = AD ⇔ ABCD est un rectangle
g (x) = - 3 x + 2
f (2) = - 6 + 2 = - 4
f ( 10) = - 30 + 2 = - 28 donc le point ∈ courbe
f (7) = - 21 + 2 = - 19 ( - 7 : - 19 )
- 3 x + 2 = 11
- 3 x = 11 - 2
- 3 x = 9
x = - 3
le reste est simple, tu poses une équation
