Question 16310
method is correct but you made simple signing error.
also 6 mysteriously disappeared between 3rd and 4th line.
19-(2x+3)=2(x+3)+x ok remove brackets
19-2x-3=2x+6+x note sign changes on 3.you are actually doing 19-(+3)
16-2x=3x+6   you have summed like terms here
now collect like terms on same side(don't forget the 6)
also when they change sides they change sign
16-6=3x+2x
10=5x divide both sides by 5
2=x
or
x=2 same thing
substitute x in original with 2 to check
hope this helps
Pete