Step 2 is expressed as follows
[tex]-2x-3=x-18[/tex]
To move to step 3 we have to add 2x to both sides of the equation like so
[tex]\begin{gathered} -2x+2x-3=x+2x-18 \\ -3=3x-18 \end{gathered}[/tex]
Therefore we used addition property of the equality .
