Here's the question you clicked on:
zippynjeri
show that the sum of the slope mf+mg=sum of the slope m(f+g)
\[LHS=m(f+g)\] \[=(m\times f)+(m\times g)\]
Finish it off and after the RHS equals the LHS, just write down =LHS at the end of your working.
It's meant to be \[RHS=m(f+g)\] Not \[LHS\]