When I solve this differential equation with NDSolve, I get a numerical solution for H[x]:

**Code for the differential equation:**

```
sol1 = NDSolve[{(H'[{(H'[{(H'[{(H'[x]) ^ 2 - ((1 + 6 H[x]^ 2) ^ 2 H[x]^ 2) / (
6 (1 + 18 H[x]^ 2)) + ((1 + 6 H[x]^ 2) ^ 2 E ^ -x) / (
18 (1 + 18 H[x]^ 2)) == 0, H[0] == 1}, H, {x, 0, 20}]
```

I want to use the numerical solution (the solution I get for the equation above) to numerically solve this equation (I want to obtain x

**Code for the equation that I want to solve.**

```
X & # 39;
```

Thank you!!