Sagot :
a=(x-3) (x+2)
=x²+2x-3x-6
=x²-x-6
b= (y+2) (y-3)
=y²-3y+2y-6
=y²-y-6
c=(4x+1) (5-x)
=20x-4x²+5-x
=-4x²+19x+5
d= (5y-2) (y+3)
=5y²+15y-2y-6
=5y²+13y-6
a = x² + 2x - 3x -6
a = x² -x -6
b = y² - 3y + 2y -6
b = y² -y -6
c = 20x -4x² +5 - x
c = 4x² -19x +5
d = 5y² +15y -2y -6
d = 5y² +13 y -6
voilà voilà ;)