Factorize algebraic expressions: (a + 7) (a – 10) + 16

We have,

(a + 7) (a – 10) + 16

a² – 10a + 7a – 70 + 16

a² – 3a – 54

By considering, p+q = -3 and pq = -54

So we can replace -3a by 6a – 9a

-54 by 6 × -9

a² – 3a – 54 = a² + 6a – 9a – 54

= a (a + 6) -9 (a + 6)

= (a – 9) (a + 6)