Classify the following polynomials as polynomials in one variable, two variables etc.
(i) x2 + x + 1
(ii) y3 – 5y
(iii) xy + yz + zx
(iv) x2 – 2xy + y2 + 1
(i) x2 + x + 1 is a polynomial in one variable as it contains only one variable i.e. x.
(ii) y3 – 5y is a polynomial in one variable as it contains only one variable i.e. y
(iii) xy + yz + zx is a polynomial in three variable as it contains two variables i.e. x , y and z.
(iv) x2 – 2xy + y2 + 1 is a polynomial in two variables as it contains two variables i.e. x and y