Odpowiedź:
[tex]a)\ \ 5x^2-3x-8=5x^2+5x-8x-8=5x(x+1)-8(x+1)=(x+1)(5x-8)\\\\b)\ \ -8x^2+14x-3=-8x^2+12x+2x-3=-4x(2x-3)+(2x-3)=\\\\=(2x-3)(-4x+1)\\\\c)\ \ 9x^{2}+3x-2=9x^2+6x-3x-2=3x(3x+2)-(3x+2)=(3x+2)(3x-1)\\\\d)\ \ 2x^2-x-1=2x^2+x-2x-1=x(2x+1)-(2x+1)=(2x+1)(x-1)\\\\e)\ \ -4x^2-15x+4=-4x^2+x-16x+4=-x(4x-1)-4(4x-1)=-(4x-1)(x+4)\\\\f)\ \ -\frac{1}{2}x^2+x+12=-\frac{1}{2}(x^2-2x-24)=-\frac{1}{2}(x^2+4x-6x-24)=\\\\=-\frac{1}{2}(x(x+4)-6(x+4))=-\frac{1}{2}(x+4)(x-6)[/tex]
