developpe et reduis : A = -15-9(-5+3b) B = -5(6-3z)-9+z C = 12x-4(6-3x) aider moi svp

Bjr,


[tex]
A = -15-9(-5+3b)\\A = -24(-5+3b)\\A = -24\times (-5) + (-24)\times 3b\\\boxed{A = 120 - 72b}\\\\B = -5(6-3z)-9+z\\B = -5\times6 - 5 \times (-3z) -9 +z\\B = -30 +15z -9 + z\\\boxed{B = -39 +16z}\\\\C = 12x-4(6-3x)\\C = 12x\times 6 -12x\times 3x -4\times 6 -3x\times (-4)\\C = 72x -36x^2 -24 + 12x\\C = 84x - 36x^2 -24\\\boxed{C = -36x^2+84x-24} [/tex]