How are the expression 7-g and g-7 different?

In the first equation the 7 is first and in the second the g is first

The Big Three—Soviet leader Joseph Stalin, British Prime Minister Winston Churchill (replaced on July 26 by Prime Minister Clement Attlee), and U.S. President Harry Truman—met in Potsdam, Germany, from July 17 to August 2, 1945, to negotiate terms for the end of World War II. After the Yalta Conference of February 1945, Stalin, Churchill, and U.S. President Franklin D. Roosevelt had agreed to meet following the surrender of Germany to determine the postwar borders in Europe. Germany surrendered on May 8, 1945, and the Allied leaders agreed to meet over the summer at Potsdam to continue the discussions that had begun at Yalta. Although the Allies remained committed to fighting a joint war in the Pacific, the lack of a common enemy in Europe led to difficulties reaching consensus concerning postwar reconstruction on the European continent.

Domain is all real numbers or (-oo,oo)
*oo= infinity