<PRE><B>Question 20876</B>
The question can be written more clearly as we cannot differentiate if the expression has a Variable L or if it is a number 1. There is also a = sign and nothing on the right hand side.

Assuming the equation is 
3k+12L-5L-2k+6L

Grouping the variables together
3k -2k + 12L - 5L + 6L
k(3-2) + L(12-5+6)
k.1 + L.13

k+13L</PRE>