I am assuming you need to solve:

There are mixed numbers involved here so you need to be careful when adding mix numbers into 'Algebrator'.

There is no special notation for mixed numbers. You need to enter them as a sum, e.g. in our problem it will be 3+3/4.

So we have one solution using Integers:

And another solution using Decimals:

In 'Options' you can set how you want to solve, using Integers or Decimals: