Question

Factorise:
$x^2+15x+56$

Answer 1

$x^2+15x+56=x^2+8x+7x+56\left\{\begin{array}{cc}\because 56=8\times 7& \\ 15=8\times 7& \end{array}\right\}=x(x+8)+7(x+8)=(x+8)(x+7)Ans.$