A value of at least -3

Can someone me with this problem . show your work .

Lance lived in portugal and brazil for a total of 14 months to learn portuguese. he learned an average of 130 new words per month when he lived in portugal, and an average of 150 new words per month when he lived in brazil. in total he learned 1920 new words. write a system of equations to represent the situation. use x to represent portugal, and y to represent brazil

Find the greatest common factor of the followig monomials 21u^5v,3u^4v^6, and 3u^2v^5