Bonjour,
1) (4x-3)² = (4x)²-2(4x)(3)+3² = 16x²-24x+9
2) F = (4x-3)²-(3+x)(-9x+3)
= (16x²-24x+9)-(-27x+9-9x²+3x)
= 16x²+9x²-24x+27x-3x+9-9
= 25x²
= (5x)²
Bonjour :)
Bon courage !
