International Relations by Peu Ghosh Free Download. International Relations by Peu Ghosh Free Download. International Relations.Q:
How to solve this system of equations?
How do I solve this system of equations?
$6x + 7y = 11$
$x + 2y = 9$
$2x + 3y = 11$
$y = 4$
The answer is $x = 1, y = 2$. I don't really understand why the answer is in the form of $x + y$, how come we're adding $11$ to $6x + 7y$ and $x + 2y$?
A:
Notice that $(x+2y)+(6x+7y)=11+6x+7y=(x+2y)+7(x+y)$
Hence, $x+2y=2$
Q:
why am I getting a NullPointerException when getting system properties?
I am trying to add some extra variables to an existing servlet project. I have a class that extends HttpServlet and overrides the doGet method. The basic logic is:
when the servlet is invoked, it gets system properties
if they are null then we do some extra stuff
Here is the method that sets the system properties (called in doGet, before super.doGet(req, resp)):
protected void setEnvironmentVariables() {
String commandLine;
String dateFormat;
String javaHome;
String jreHome;
String jreVersion;
String jvmHome;
String javaExe;
String systemProps = System.getProperties().getProperty("user.home");
commandLine = "java -version | grep version | awk '{print $3}'"
+ " > " + System.getProperty("user.dir") + "/version.txt";
try {
Process p = Runtime.getRuntime().exec(commandLine);
BufferedReader input = new BufferedReader( be359ba680
Related links: