Bonjour,
a. (2x-5)(-x+1)
-2x²+2x+5x-5
-2x²+7x-5
b. (-x+7)(2x+1)
-2x²-x+14x+7
-2x²+13x+7
c. 3x(-2x-4)
-6x²-12x
d. (2x+1)²
(2x+1)(2x+1)
4x²+2x+2x+1
4x²+4x+1
e. (-5x+2)²
(-5x+2)(-5x+2)
25x²-10x-10x+4
25x²-20x+4
f. (7x+1)²
(7x+1)(7x+1)
49x²+7x+7x+1
49x²+14x+1