In order to solve this, first add 7.5 to both sides of the equation.
[tex]2x-7.5+7.5=23.50+7.5[/tex]
[tex]2x=31[/tex]
Divide 2 on both sides of the equation for x.
[tex]\frac{2x}{2}[/tex]=[tex]\frac{31}{2}[/tex]
[tex]x=\frac{31}{2}[/tex] or [tex]15.5[/tex]
