Why was President Andrew Jackson
trying to get the Eastern Tribes removed?

in order to open new land for settlement by citizens of the United States.

Explanation:

With the onset of westward expansion and increased contact with Indian tribes, President Jackson set the tone for his position on Indian affairs in his message to Congress on December 6, 1830. Jackson’s message justified the removal policy already established by the Indian Removal Act of May 28, 1830.

one of the main reasons was definitely slavery. back in 1861, republican abraham lincoln was elected and ended up being a major influence in the slavery business. slavery greatly affected the texas economy because back in 1845 during the annexation of texas, slaves became a big part of the texas population. many texans that were in favor of the secession influenced groups through party ties.