Sagot :
A = 49y² +56y+16 + 81y² -54y+9 (identité remarquable)
= 130y² +2y +25
B = 9y²-81y -(49y² +28y+4)
= 9y²-81y-49y²-28y-4
= -40y² -109y -4
c = (15y²-35y-18y+42) - (25y²+30y -30y-36)
= 15y² - 53y+42-25y²+36
= -10y²-53y +78
A=((7y)²+2X7yX4 +4²)+((9y)²-2X9yX3+3²
=49y²+56y+16+81-54y+9
=49y²+2y+106
B=9y(y-9)-(7y+2)²
=(9yXy-9yX9)-((7y)²+2X7yX2+2²)
= 9y²-81y-(49y²+28y+4)
=9y²-81y-49y²-28y-4
=40y²-109y-4