# The sum and difference of two expressions are 5x² – x – 4 and x² + 9 x – 10 respectively

The sum and difference of two expressions are 5x² – x – 4 and x² + 9 x – 10 respectively. The HCF of the two expressions will be

(a) (x + 1)

(b) (x – 1)

(c) (3x + 7)

(d) 2x – 3)