In a algebra quadratic question, it says:
The equation $3x^2+4x-k=0$ has two distinct real roots.
If 2 is a root of this equation, find the value of $k$ and the second root.
The first line of working for this question shows as:
The rest I more or less understand, but for this line of working, I get the $(x-2)$ because of a root at 2, but where does the $(3x+n)$ come from? What is $n$ and where does it come from?