Question

Factorise $x^2-21x+110$

Answer 1

$x^2-21x+110=0$

$x^2-11x-10x+110=0$

$x(x-11)-10(x-11)=0$

$(x-10)(x-11)=0$

$x=11,10$

$\therefore x=10,x=11$