Question

If 4x + 5 = 13x + 4 – x – 9, then x = ?

Answer 1

Are you supposed to combine like terms? the 4x and the 13x?

Answer 2

Yes, combine both terms. But firstly, you need to simplify both sides of the equation, like so
\[4 x + 5 = 13 x + 4 − x − 9\]
\[4 x + 5 = 13 x + 4 + − x + − 9\]
Here you combine terms \[4 x + 5 = ( 13 x + − x ) + ( 4 + − 9 )\]