# Multivariable Polynomials Exercises

### Example 1

Is the following expression a multivariable polynomial? If not, explain why:

*x* + *xy* – *y*

### Example 2

Is the following expression a multivariable polynomial? If not, explain why:

### Example 3

Is the following expression a multivariable polynomial? If not, explain why:

π*x*^{2} + 3.4*xy*^{4} + *x*^{2}*y*^{5} – 11

### Example 4

Is the following expression a multivariable polynomial? If not, explain why:

*x* + *y* + 9^{(-1)}

### Example 5

Is the following expression a multivariable polynomial? If not, explain why:

5*xy* – *y*^{7} + *x*^{ - 4}*y*^{4}