Bonsoir,
A= 4x² -12x +9 + 15x² +5x -3x -1
= 19x² -10x +8
B= 6 -2x -5x +7
= -7x +13
C= 4x² +12x +9 + 9x² -1
= 13x² +12x +8
D= (4 -16x ) (3x+5)
= 12x +20 -48x²- 80x
= -48x² -68x +20
E= 2x² -( 24x -36x² -4 +6x)
= 2x² - 24x +36x² +4 -6x
= 38x² -30x +4
