Zadanie 17
[tex]x+(1-x(1-x))=x+(1-x+x^2)=\\\\=x+1-x+x^2=\boxed{x^2+1}[/tex]
Zadanie 19
[tex](3z+4)(z-6)=3z^2-18z+4z-24=\boxed{3z^2-14z-24}\\\\\frac{16x-6y}{2}-\frac{9x+6y}{3}=\frac{2(8x-3y)}{2}-\frac{3(3x+2y)}{3}=8x-3y-(3x+2y)=\\\\=8x-3y-3x-2y=\boxed{5x-5y}[/tex]
