What are common causes of syntax errors in PHP code?

Common causes of syntax errors in PHP code include missing semicolons at the end of statements, mismatched parentheses or curly braces, and incorrect variable names or function calls. To solve syntax errors, carefully review your code for any missing or misplaced characters and ensure that all syntax rules are followed. Example:

// Incorrect code with missing semicolon
$variable = "Hello"
echo $variable;
```

To fix the syntax error, add a semicolon at the end of the first statement:
```php
// Corrected code with semicolon added
$variable = "Hello";
echo $variable;