If x is a negative real number, then which of the following are not correct?

1. There is some natural number k such that kx > 0

2. x² + x > 0 always

3. 2x < x < -x

4. x² is always a rational number

Select the correct answer using the code given below:

Given:

Condition is x is a negative real number

Calculation:

Case 1.

If we multiply a natural number with a negative real number we will always get a negative number 

eg. 1 × -2 = -2 

Hence, Case 1 is wrong

Case 2.

If we take x = – 1

(– 1)² + (– 1)

⇒ 1 – 1 = 0 which is not ≥ 0

Hence, Case 2 is also wrong

Case 3.

If we take x = – 1

2 × (– 1) < (– 1) < –(– 1)

–2 < – 1 < 1

Hence, Case 3 is correct

Case 4.

If we take real number x = -3^1/4 then we get 

x² = 3^1/2 which is not a rational number

Hence, Case 4 is also wrong

∴ 1, 2, and 4 are not correct