(i) Polynomial in one variable x.
(II) 4x2−3x+7
It is a polynomial in one variable, y.
(iii) 3√t+t√2 is not a polynomial as power of t in √t is not a whole number.
(iv) y+2y is not a polynomial as power of y in second term, i.e., 1y=y−1 is not a whole number.
(v) x10+y3+t50 is not a polynomial in one variable but a polynomial in three variables x, y and t.