#include<stdioh.h>
void?main()
{
float?x;
printf("x=");
scanf("%f",&x);
printf("y=",-(x+4)/2);
}
//38
#include<stdio.h>
void?main()
{
float?x1,y1,x2,y2,k,b;
scanf("%f%f%f%f",&x1,&y1,&x2,&y2);
k=(y1-y2)/(x1-x2);
b=y1-k*x1;
printf("y=%fx+%f",k,b);
}
//39
#include<stdio.h>
void?main()
{
float?a[5],sum=0;
int?i;
for(i=0;i<5;i++)
{
scanf("%f",&a[i]);
sum=sum+a[i];
}
printf("sum=%f,ave=%f",sum,sum/5);
}