Factorise:

The given expression is $y^{2}+19 y+60$.

Find two numbers that follow the conditions given below:

Sum $=19$

Product $=60$

Clearly, the numbers are 15 and $4 .$

$y^{2}+19 y+60=y^{2}+15 y+4 y+60$

$=y(y+15)+4(y+15)$

$=(y+15)(y+4)$