[tex]2x+8=28[/tex]
First we have to substract 8 from both terms. This way the 8 in the left term disappears:
[tex]\begin{gathered} 2x=28-8 \\ 2x=20 \end{gathered}[/tex]
And now we divide both terms by 2, so that in the left term we only have x:
[tex]x=\frac{20}{2}=10[/tex]
The answer is the first option, x = 10
