Odpowiedzi

2009-12-10T20:23:13+01:00
A)(5y+1)(1-5y)-5(4x+1)(1-4x)=4(5y-25y²+1-5y)-5(4x-16x²+1-4x)=20y-100y²+4-20y-20x+80x²-5+20x=100y²-1+80x²
B)(x+2y)²+(2x-y)²-5(x+y)(x+y)= x²+4y²+4x²-y²-5(x²+xy+yx+y²)=
x²+4y²+4x²-y²-5x²-5xy-5xy -5y²=-2y²