bonjour
b= -7y²( -5 -2y²)
= 35y² +14y ^4 (35x² +14 y puissance 4)
e = (4-a)²
= 4² - (2×4×a) +a²
=16 - 8a +a²
=a² -8a +16
f=(2x +3)²
=4x² +12x +9
h= (x+4) (x -6) + (-1 +x) (x -7)
= x²-6x+4x-24 + (-x+7+x²-7x)
= x²-6x+4x-24 -x+7+x²-7x
=2x² -10x -17
i= -3 (a²+2) - (a- 3) (2a +7)
= -3a² -6 - (2a² +7a-6a-21)
=-3a²-6-2a²-7a+6a+21
= - 5a² -a +15
j= 4 - (2x +1)²
= 4 -(4x² +4x+1)
= 4-4x² -4x -1
= - 4x² -4x + 3