Question:
Factorise:
7y2 − 19y − 6
Solution:
The given expression is $7 y^{2}-19 y-6$.
Find two numbers that follow the conditions given below:
Sum $=-19$
Product $=7 \times-6=-42$
Clearly, the numbers are $-21$ and 2 .
$7 y^{2}-19 y-6=7 y^{2}-21 y+2 y-6$
$=7 y(y-3)+2(y-3)$
$=(7 y+2)(y-3)$