Can you solve this equation?（二分）

#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>
#include <iostream>
using namespace std;
double result(double x)
{
return 8*pow(x,4)+7*pow(x,3)+2*pow(x,2)+3*x+6;
}
int main()
{
//freopen("in.txt","r",stdin);
// freopen("out.txt","w",stdout);
int t,i;
double y,x,l,r,mid;
scanf("%d",&t);
while(t--)
{
scanf("%lf",&y);
if(result(0.0)>y||result(100.0)<y)
{
printf("No solution!\n");
}
else
{

l=0.0;r=100.0;
while(r-l>1e-7)
{
mid=(l+r)/2;
if(result(mid)>y)
r=mid-1e-7;
else
l=mid+1e-7;
}
printf("%.4lf\n",l);
}
}
return 0;
}