Classify the following polynomials as polynomials in one-variable, two variables etc. :
(i) `x^2-x y+7y^2`
(ii) `x^2-2t x+7t^2-x+t`
(iii) `t^3-3t^2+4t-5`
(iv) `x y+y z+z x`

Explanation

(i) `x^2-x y+7y^2`:It is a two variable polynomial.`(x` and `y)`
(ii) `x^2-2t x+7t^2-x+t`:It is a two variable polynomial.`(x` and `t)`
(iii) `t^3-3t^2+4t-5`:It is a one variable polynomial.`(t)`
(iv) `x y+y z+z x`:It is a three variable polynomial.`(x`, `y` and `z)`