Bonjour,
Développer:
I= 2(6y-5)²-12+10y
I= 2(36y²-30y-30y+25)-12+10y
I= 72y²-120y+50-12+10y
I= 72y²-110y+38
J= (1+9x)(1-9x)+(3x+7)²
J= 1-9x+9x-81x²+9x²+21x+21x+49
J= - 72x²+42x+50
K= 6x²-18-(x-4)²
K= 6x²-18-(x²-4x-4x+16)
K= 6x²-18-x²+8x-16
K= 5x²+8x-34