Explanation: The Americans wanted to expand to the west, because they could see that in that part of the American territory, an important economic phenomenon was occurring that would positively change their lives such as the gold rush, an event that occurred specifically in California and that aroused the interest of many Americans who chose to expand into that area. The West had many gold deposits found in rivers and streams that changed the lives of many Americans.
In the same way, they were willing to go to war to secure the west because they wanted to take over Texas, State, belonging to Mexico at that time and that represented as such huge economic and geographical interests for the Americans in their expansionist intensities.