Need help quick please need it really bad

[tex]7x + 3 = 4x + 15[/tex]
Both sides minus 3
[tex]7x = 4x + 15 - 3[/tex]
[tex]7x = 4x + 12[/tex]
Both sides minus 4x
[tex]7x - 4x = 12[/tex]
[tex]3x = 12[/tex]
Divided both sides by 3
[tex]x = \frac{12}{3} \\ [/tex]
[tex]x = 4[/tex]