can a mac 2007 24-inch upgrade ram to 8gb?

The max a 2007 will address is 6GB or RAM which means a 4 GB DIMM in one slot and the other slot a 2 GB DIMM.

You can insert 2 4GB RAM modules but as explained, a 2007 iMac can only address 6GBs out of the 8GBs.

No, please read my initial answer.