3x²y-(2x²y-xy)+(2xy-yx²) при xy=3

Question

3x²y-(2x²y-xy)+(2xy-yx²) при xy=3

Comments

при xy=-3. там ошибка

Answer 1

=3x²y-2x²y+xy+2xy-x²y=3xy

при ху=3 получим 3ху=3·3=9.