Odpowiedź:
[tex](x^3+5)(2x-6)=x^3\cdot2x-6x^3+5\cdot2x-5\cdot6=2x^4-6x^3+10x-30\\\\\\(5x^2-x)(x^2+2x+2)=5x^2\cdot x^2+5x^2\cdot2x+5x^2\cdot2-x^3-x\cdot2x-2x=\\\\=5x^4+10x^3+10x^2-x^3-2x^2-2x=5x^4+9x^3+8x^2-2x\\\\\\(x-4)(x+8)=x^2+8x-4x-4\cdot8=x^2+4x-32[/tex]
