Question: Factorise:
z2 + 12z + 27
Solution:
The given expression is $z^{2}+12 z+27$.
Find two numbers that follow the conditions given below:
Sum $=12$
Product $=27$
Clearly, the numbers are 9 and $3 .$
$z^{2}+12 z+27=z^{2}+9 z+3 z+27$
$=z(z+9)+3(z+9)$
$=(z+9)(z+3)$
