Odpowiedzi

2010-03-31T18:56:35+02:00
(5x+4)(5x-4)-(5x-2)² =25x²-16-(25x²-20x+4)=25x²-16-25x²+20x-4 =20x-20

1/4(b+2a)-(1/2b-a)² = 1/4b+1/2a-(1/4b²-ab+a²)=
=1/4b+1/2a-1/4b²+ab-a²=-a²-1/4b²+ab+1/2a+1/4b

-2x(x-y)+(y-3)²+(y-3x)(y+3x)+2xy = -2x²+2xy+y²-6y+9+y²-9x=
=-2x²+2y²+2xy-9x-6y+9

(x∫2-1)(x∫2+1)-2(x+2)²+(2x-1)²+8 = 2x²-1-2(x²+4x+4)+4x²-4x+1=
=2x²-1-2x²-8x-8+4x²-4x+1=4x²-12x-8