Répondre :
A = (3x-10)(2x-7)-(8x-9)(6x-7)
= (6x²-21x-20x+70)-(48x²-56x-54x+63)
= 6x²-21x-20x+70-48x²+56x+54x-63
= -42x²+69x+7
= (6x²-21x-20x+70)-(48x²-56x-54x+63)
= 6x²-21x-20x+70-48x²+56x+54x-63
= -42x²+69x+7
A = (3x - 10) (2x -7) - (8x-9) (6x-7)
=6x²-21x-20x+70-(48x²-56x-54x+63)
=6x²-21x-20x+70-48x²+56x+54x-63
= -42x²+69x+7
=6x²-21x-20x+70-(48x²-56x-54x+63)
=6x²-21x-20x+70-48x²+56x+54x-63
= -42x²+69x+7