Répondre :
3(x-1)²+13
=3(x²-2x+1)+13
=3x²-6x+3+13
=3x²-6x+16
C(x)=(2x-5)²-x²+14x-9
=4x²-20x+25-x²+14x-9
=3x²-6x+16
donc C(x)=3(x-1)²+13
3(x-1)²+13
=3(x²-2x+1)+13
=3x²-6x+3+13
=3x²-6x+16
C(x)=(2x-5)²-x²+14x-9
=4x²-20x+25-x²+14x-9
=3x²-6x+16
donc C(x)=3(x-1)²+13