Question

Factorise:

$7y^2-19y-6$

Answer 1

$7y^2-19y-6=7y^2-21y+2y-6\left\{\begin{array}{c}\because 7\times (-6)=-42\\ \therefore -42=-21\times 2\\ -19=-21+2\end{array}\right\}=7y(y-3)+2(y-3)=(y-3)(7y+2)$