Sagot :
[tex]9n+4=5n+18\ \ \ \ |subtract\ 4\ from\ both\ sides\\\\9n=5n+14\ \ \ \ \ |subtract\ 5n\ from\ both\ sides\\\\4n=14\ \ \ \ \ \ |divide\ both\ sides\ by\ 4\\\\n=\frac{14}{4}\\\\n=\frac{7}{2}\\\\\boxed{n=3\frac{1}{2}}[/tex]
[tex]9n+4=5n+18\\9n-5n=18-4\\4n=14\ /:4\\n=3.5\\\\Ans.\ n=3.5[/tex]