Answer:
x + y + 1
or
xy + y² + 2
or
x² + y² - 1
or
a²b + b³ + 3
Explanation:
You can use x and y as the two variables. Then add them to make is x + y (this is already two variables and two terms). Add a constant, say 1. So x + y + 1, now we have three terms with two different variables and one constant.
Or you can also make it xy + y² + 2 or x² + y² - 1 by adding exponents to each of the variable.
You can choose one from the above or you can make your own (it depends on you).