Odpowiedzi

2009-12-16T15:03:12+01:00
A) 7x²-21x-14-3x²+18x-3= 4x²-3x-17

4(-0,2)²-3(-0,2)-17=0,16+0,6-17=-16,24

b)x(3xy-y)-y(x²-xy+x)=
=3x²y-xy-x²y+xy²-xy=
=2x²y-2xy+xy²

2*(-1)²*⅕ - 2*(-1)*⅕ + (-1)*(⅕)²=
=⅖+⅖-1/25=4/5-1/25=20/25-1/25=19/25=0,76