Question

how to factorise:(lm+l)+m+1

Answer 1

(lm+l)+m+1

l(m+1) +1(m+1)

(m+1) (l+1)

Answer 2

FULL ANSWER WITH STEPS

$(lm+l)+m+1$
$=lm+l+m+1$
$=(ml+m)+(l+1)$       [ $lm$ can also be written as $ml$. ]
$=m(l+1)+1(l+1)$
$=(m+1)(l+1)$
Here's your answer ! 

Hope this may help you. 

If you have any doubt, then you can ask me in the comments.