Question

Va rog frumos exerciutiul 8 :)

Answer 1

8.
a)x²-2x-3=x²+x-3x-3=x(x+1)-3(x+1)=(x+1)(x-3)
b)2x²-x-3=2x²-3x+2x-3=x(2x-3)+(2x-3)=(2x-3)(x+1)
c)3x²+x-1=[x+(-1+√13)/6][x-(-1-√13)/6]=[x-(1-√13)/6][x+(1+√13)/6]
Δ=1+4*3=13
x₁=(-1+√13)/6
x₂=(-1-√13)/6
d)-3x²-5x-2=-3x²-2x-3x-2=x(-3x-2)+(-3x-2)=(-3x-2)(x+1)
e)-x²+3x+4=4x+4-x²-x=4(x+1)-x(x+1)=(x+1)(4-x)
f)2x²-3x+1=2x²-2x-x+1=2x(x-1)-(x-1)=(x-1)(2x-1)