Répondre :
f(x)=(x-1)(11-x)+5(x-1)²
=(11x-x²-11+x)+5(x²-2x+1)
=11x-x²-11+x+5x²-10x+5
=4x²+2x-6
=(11x-x²-11+x)+5(x²-2x+1)
=11x-x²-11+x+5x²-10x+5
=4x²+2x-6
f(x)=(x-1)(11-x)+5[tex](x-1)^{2}[/tex]