```
text = {"Donc", "j'obtiens", "<i>aᵢ₁(\[Alpha]₁ - \[Beta]₁) + aᵢ₂(\[Alpha]₂ - \
\[Beta]₂) + ... + aₙ₁(\[Alpha]ₙ - \[Beta]ₙ) = bᵢ - bᵢ = 0.</i>", \
"<i>aᵢ₁(\[Alpha]₁ - \[Beta]₁) + aᵢ₂(\[Alpha]₂ - \[Beta]₂) + ... + \
aₙ₁(\[Alpha]ₙ - \[Beta]ₙ) = bᵢ - bᵢ = 0.</i>", "Donc en particulier", \
"ça veut dire que si je multiplie par <i>c</i>", "pour tout nombre réel \
<i>c</i>"}

```

Now my question is: 

1. How can I get the position of in the list of every object that starts with `<i>`?
2. How can I replace the `<i>` at the start of that object and the `</i>` at the end of that object by another string ?

By "object" I really mean a list object: for instance, I don't want the `<i>` and `</i>` to be replaced in "ça veut dire que si je multiplie par `<i>c</i>`", since this object of the list does not start with an `<i>`. 

EDIT: To clear any confusion, here is how the text could look like afterwards:

```
"Donc", "j'obtiens", "REPLACE(\[Alpha]₁ - \[Beta]₁) + aᵢ₂(\[Alpha]₂ - \
    \[Beta]₂) + ... + aₙ₁(\[Alpha]ₙ - \[Beta]ₙ) = bᵢ - bᵢ = 0.REPLACE", \
    "REPLACEaᵢ₁(\[Alpha]₁ - \[Beta]₁) + aᵢ₂(\[Alpha]₂ - \[Beta]₂) + ... + \
    aₙ₁(\[Alpha]ₙ - \[Beta]ₙ) = bᵢ - bᵢ = 0.REPLACE", "Donc en particulier", \
    "ça veut dire que si je multiplie par <i>c</i>", "pour tout nombre réel \
    <i>c</i>"

```