How beneficial was the US expansion in the 1800s?

The were beneficial,because they introduced lots of new technologies,and techniques to the world.

Explanation:  

Multiple things were built during this time and allowed the U.S. and the world to change and develop,they mostly used the slaves power and they develop of their operation,to make new technologies,like the cotton plow. But also be able to use the new knowledge and share.

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step-by-step explanation:

100%     = 120

1%= 120/100=   1.2

9%   = 1.2 x 9=     10.8

10.80 to the 120 to get $130.80