Factorize algebraic expressions: x2 + 12x – 45

We have,

x² + 12x – 45

To factorize the given expression we have to find two numbers p and q such that p+q = 12 and pq = -45

So we can replace 12x by 15x – 3x

-45 by 15 × 3

x² + 12x – 45 = x² + 15x – 3x – 45

= x (x + 15) – 3 (x + 15)

= (x – 3) (x + 15)