Complex sentence: The U.S. sought the land as a better route for the construction of the southern transcontinental railway line, and the financially-strapped government of Antonio López de Santa Anna agreed to the sale, which netted Mexico $10 million (equivalent to $in).
Split into simpler sentences: The U.S. sought a better route for the construction of the southern transcontinental railway line. The financially-strapped government of Antonio López de Santa Anna agreed to the sale, which netted Mexico $10 million (equivalent to $in).