Question

which of 2 and root 2 is a zero of the polynomial p(x)=x*3-2x​

Answer 1

Answer: √2

Step-by-step explanation:

x³ - 2x  = 0

x(x² - 2) = 0

x (x+√2)(x-√2) =0

⇒ x = 0 , ±√2

from the options, √2 is the zero of p(x) = x³ - 2x

∴√2 is the root of the given equation

                              (0R)

(by substituting values of both options)

Option 1 :

x = 2

2³- 2×2 = 0

8-4 = 0

4≠0

LHS ≠ RHS

Option 2 :

x = √2

(√2)³ - 2(√2) =0

2√2 - 2√2 = 0

LHS = RHS

∴√2 is the root of the given equation