Odpowiedzi

2010-01-08T17:46:09+01:00
A
2x²-6x-x²-2x-x-2=4x²-12x+9
-3x²-3x=11
-3x² -3x-11=0
i dalej zdelta chyba co?

b
x²-x-2x+2≥-4x²+4x-1+1
3x²-7x≥-2

dalej nie wiem ;/
2010-01-08T17:50:16+01:00
2x(x-3) - (x+1)(x+2) = (2x-3)²
2x²-6x-(x²+2x+x+2)=4x²-12x+9
2x²-6x-x²-3x+2=4x²-12x+9
x²-9x+2=4x²-12x+9
-3x²+3x-7=0



(x-2)(x-1) ≥ -(2x-1)² +1
x²-x-2x+2≥-4x²+4x-1+1
x²-3x+2≥-4x²+4x
5x²-7x+2≥0
Δ49-4*2*5=9
√Δ=3

x₁=(7-3)/2=2
x₂=((7+3)/2=5