Answer
$3$
Work Step by Step
According to the Sum of Rank and Nullity Theorem (the sum of the rank and the nullity of $T$ equal the dimension of the domain),
$Rank(T)=dim(\rm I\!R^5)-nullity(T)=5-2=3$.
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.