Odpowiedzi

2010-01-07T16:45:13+01:00
3x²+y²-2xy-(-xy-2y²+2x²) =
3x²+y²-2xy+xy+2y²-2x² =
x²+3y²-xy

(-2)²+3(√5)²-(-2*√5) =
4+3*5-(-2√5) =
4+15+2√5 =
19+2√5