Question: Factorise:
z2 + 19z − 150
Solution:
The given expression is $z^{2}+19 z-150$.
Find two numbers that follow the conditions given below:
Sum $=19$
Product $=-150$
Clearly, the numbers are 25 and $-6$.
$z^{2}+19 z-150=z^{2}+25 z-6 z-150$
$=z(z+25)-6(z+25)$
$=(z+25)(z-6)$
