Explain how the Treaty of Guadalupe Hidalgo changed the United States' southern border.

It doubled the size of the United States.

Explanation:

The Treaty of Guadalupe Hidalgo had changed the United States' southern border because Mexico agreed to give up all claims to Texas and accept the Rio Grande as the boundary of that United state of America. The United States and Mexico signed the treaty of Guadalupe-Hidalgo on February 2, 1848. Due to this treaty, the size of Mexico is halved whereas doubled the size of the United States.

pepin the short[a] (german: pippin der kurze, french: pépin le bref, c. 714 – 24 september 768) was the king of the franks from 751 until his death. he was the first of the carolingians to become king.[b][2]

the younger son of the frankish prince charles martel and his wife rotrude, pepin's upbringing was distinguished by the ecclesiastical education he had received from the monks of st. denis. succeeding his father as the mayor of the palace in 741, pepin reigned over francia jointly with his elder brother carloman. pepin ruled in neustria, burgundy, and provence, while his brother carloman established himself in austrasia, alemannia and thuringia. the brothers were active in suppressing revolts led by the bavarians, aquitanians, saxons, and the alemanni in the early years of their reign. in 743, they ended the frankish interregnum by choosing childeric iii, who was to be the last merovingian monarch, as figurehead king of the franks.