Barbiefan1475 are those format closed source since im not sure if libreoffice supports it
DOCX/XLSX/PPTX is an open format (not open source) XML-based format. The format is complicated and governed by the Office Open XML standard, which is published. Because Office Open XML is open format, rather than open source, the the standard must be reverse-engineered to some degree, with varying degrees of success by different application developers.
The bottom line is, as I understand it, that OpenOffice can read and modify DOCX/XLSX/PPTX formats, but not write to those formats, but LibreOffice can read, modify and write to DOCX/XLSX/PPTX formats. Depending on your school's requirements, that might be something you should consider when making a choice.
For what it is worth, I've had no difficulty reading, modifying and writing DOCX and XLSX documents using LibreOffice, but I understand that complex, heavily formatted documents/spreadsheets can cause difficulties because of the complexity of the DOCX/XLSX/PPTX standard.