Odpowiedzi

2010-02-07T18:27:27+01:00
(2x+5)(3-x)-(1-x)² =
= 6x-2x²+15-5x -2+2x-x²=
=-3x²+3x+12 / całość ÷ (-3)
= x²-x -4

x=-2
x²-x -4=
= (-2)²-(-2)- 4=
= -4 +2 -4=
= -6