23. developper chaque expression a) (3 - 4x)² b) (10 + 9x) (10 - 9x) c) (3y + 6)² d) (8x - 6y) (8x + 6y)

a) (3-4x)²
=9-24x+16x²

b)(10+9x)(10-9x)
=100-90x+90x-81x²
=-81x²+100

c)(3y+6)²
=9y²+36y+36

d)(8x-6y)(8x+6y)
=64x²+48xy-48xy-36y²
=64x²-36y²