Question: Factorise:
x2 − 4x − 12
Solution:
The given expression is $x^{2}-4 x-12$.
Find two numbers that follow the conditions given below :
Sum $=-4$
Product $=-12$
Clearly, the numbers are $-6$ and 2 .
$x^{2}-4 x-12=x^{2}-6 x+2 x-12$
$=x(x-6)+2(x-6)$
$=(x-6)(x+2)$
