bonjour
B (x)= - x² + 20 x - 64
- x² + 20 x - 64 = 0
Δ = 400 - 4 ( - 1 * - 64 ) = 400 - 256 = 144 = 12 ²
x 1 = ( - 20 - 12 ) / - 2 = - 32 /- 2 = 16
x 2 = ( - 20 + 12 ) / - 2 = - 8 / - 2 = 4
volume maximal = 16 T
B ( 16 ) = ( - 16 )² + 20 *16 - 64 = 256 + 320 - 64 = 512 (en centaine d'€ )
