bonjour
f (x) = ( 3 x + 1 ) ( x - 4 ) - ( 3 x + 1 ) ( 2 x - 2 )
f(x) = ( 3 x + 1 ) ( x - 4 - 2 x + 2 )
f (x) = ( 3 x + 1 ) ( - x - 2 )
f ( -2) = ( - 2 + 1 ) ( 2 - 2 ) = 0
f ( 3) = ( 9 + 1 ) ( - 3 - 2 ) = 10 * - 5 = - 50
f ( 1) = ( 3 + 1 ) ( - 1 - 2 ) = 4 * - 3 = - 12