bonsoir
Developper :
a) (x-1) (4-x) = 4x-x²-4+x = -x²+5x-4
b) (3x + 5)² =9x²+30x+25
a) 3 (5x - 1) + 7 ( 4x² - 3x + 1) = 15x-3+28x²-21x+7 =28x²-6x+4
b) 5 ( 2x + 3)² + (x+2) (x+1) = 5(4x²+12x+9) +x²+x+2x+2 =20x²+60x+45+x²+3x+2= 21x²+63x+47
c) ( 5x + 3) ( 5x- 3) + 8 (x-1) = 25x²-9 +8x-8 = 25x²+8x-17
Factoriser:
a) 3 (x+2) - (7x-5) (x+2)
(x+2)(3-7x+5)
(x+2)(-7x+8)
b) ( 2x-5)² + (4x+ 1) ( 2x - 5)
(2x-5)(2x-5+4x+1)
(2x-5)(6x-4)
2(2x-5)(3x-2)
c) (x-2)² - (8x + 6)²
(x-2-8x-6)(x-2+8x+6)
(-7x-8)(9x+4)