land use data coordinates

Hello,
I am new to ArcGIS. I am working on creating a watershed. I have created the watershed using the arcToolbox hydrology tools. That worked fine. The problem is I downloaded two land use files for two states. They are .tif files. When I added them as a layer to my .mxd they are not aligned. How do I get them aligned? The coordinate system is different for my .mxd and the two .tif land use files.