Which of the following expressions are polynomials in one variable and which are not? State reasons for your answer:
(i) 3x2-4x+15
(ii) y2+2
(iii) 3+
x
(iv) x-
(v) x12+y3+t50
(i) 3x2-4x+15 is a polynomial of one variable x.
(ii) y2+2is a polynomial of one variable y.
(iii) 3+
x is not a polynomial as the exponent of 3
is not a positive integer.
(iv) x - is not a polynomial as the exponent of -
is not a positive integer.
(v) x12+y3+t50 is a polynomial of three variables x, y, t.