Hello,
[tex]3x + 4 = 8[/tex]
[tex]3x + 4 - 4 = 8 - 4[/tex]
[tex]3x = 4[/tex]
[tex] \frac{3x}{3 } = \frac{4}{3} [/tex]
[tex]x = \frac{4}{3} [/tex]
