What factor is common to all the expressions x

^{2}– x, 2x^{2}+ x – 1 and x^{2}– 1?-
**A.**

x -
**B.**

x + 1 -
**C.**

x – 1 -
**D.**

No common factor -
**E.**

(2x – 1)

##### Correct Answer: Option D

##### Explanation

x^{2} – x = x(x – 1)

= 2x^{2} + x – 1

= (2x – 1)(x + 10

x^{2} – 1 = (x + 1)(x – 1)

No factor