Question

Which of the following is NOT a root of x (x+3)(x-1)(2x+1)= 0

i. 0
ii. -3
iii. -1
iv. 1/2

A. i only B. iv only
C. i and ii only
D. iii and iv only​

Answer 1

The answer is A only i. (0)

Answer 2

D

Explanation:

Given

x(x + 3)(x - 1)(2x + 1) = 0

Equate each factor to zero and solve for x

x = 0

x + 3 = 0 ⇒ x = - 3

x - 1 = 0 ⇒ x = 1

2x + 1 = 0 ⇒ 2x = - 1 ⇒ x = -
`(1)/(2)`

Thus

x = 0, x = - 3, x = 1, x = -
`(1)/(2)` are the roots

Hence

111 x = - 1 and iv x =
`(1)/(2)` are NOT roots → D