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markdown 入门

$$x = \dfrac{-b \pm \sqrt{b^2 - 4ac}}{2a}$$

code format

#include<stdio.h>
int main(int argc,char* argv[]){
    printf("hello world");
    return 0;
}

pubic class First{
    public static void  main(String []args){
        System.out.println("hello world");
    }
}

def say():
    print "hello world"

def say():
    print "hello world"

math formulate(latex format)

$$x = \dfrac{-b \pm \sqrt{b^2 - 4ac}} {2a}$$

$$x = \dfrac{-b \pm \sqrt{b^2 - 4ac}}{2a}$$