a)
[tex]2x^2-xy^2-5x^2+2xy^2=-3x^2+xy^2[/tex]
Po podstawieniu [tex]x=\frac{1}{3}, y=9[/tex]
[tex]-3*(\frac{1}{3})^2+\frac{1}{3}*9^2=-3*\frac{1}{9} +\frac{1}{3} *81=-\frac{1}{3} +27=26\frac{2}{3}[/tex]
b)
[tex]-\frac{1}{2}x^3y-\frac{2}{3}xy+\frac{1}{2}x^3y-\frac{1}{3}xy=-xy[/tex]
Po podstawieniu:
[tex]-\frac{1}{3}*9=-3[/tex]
