PDF chapter test TRY NOW

Classify the following polynomials as polynomials in one variable, two variables etc.
 
i. \(x^2 + x + 1\) is a
 
ii. \(y^3 – 5y\) is a
 
iii. \(xy + yz + zx\) is a
 
iv. \(x^2 – 2xy + y^2 + 1\) is a
Answer variants:
Polynomial in two variable
Polynomial in one variable
Polynomial in three variable