Obliczenia
[tex]-(a-1)(\frac{1}{2}a-2)=-(\frac{1}{2}a^2-2a-\frac{1}{2}a+2)=\\\\=-(\frac{1}{2}a^2-2\frac{1}{2}a+2)=\underline{-\frac{1}{2}a^2+2\frac{1}{2}a-2}[/tex]
