Réponse :
Explications étape par étape
Bjr,
A = 4(x-25)
B= (5x+1) ( 1-2x +1-3x) = (5x+1) ( -5x +2)
C= Il ne manque pas quelque chose?
4(x-25) = 0 => x-25 =0 => = x = 25
4(x-25) =69 => 4x-100 =69 => 4x = 69 +100 = 169
x = 169/4 = 42,25
(5x+1) ( -5x +2) =0
Soit
5x+1 = 0 => 5x = -1 => x = -1/5
Soit
-5x+2 = 0 => 2=5x => x = 2/5
☺