Question 1. Which of the Following Expressions are Polynomials in Exercise 2.1 Chapter 2 Polynomial Maths Class 9

Question 1. Which of the following expressions are polynomials in one variable and which are not? State reasons for your answer.
(i) 4x² – 3x + 7           (ii) y² + √2      (iii) 3√t + t√ 2                         (iv) y +2/y       (v) x¹⁰ + y³ + t⁵⁰

Solution (i)4x² – 3x + 7           
there is only one variable x with whole number power so this polynomial in one variable

(ii)y² + √2                  
there is only one variable y with whole number power  so this polynomial in one variable

(iii) 3√t + t√ 2                        
there is only one variable t but in 3√t  power of t is ½ which is not a whole number so 3√t + t√ 2 is not a polynomial

(iv)y +2/y                   
there is only one variable y  but 2/y = 2y-1  so the power is not a whole number  so y +2/y is not a  polynomial

(v) x¹⁰ + y³ + t⁵⁰            
there  are three variable x  y and t and there powers are whole number so this polynomial in three variable