3x-5y=7
9x+10y=1
solve the following system by addition?

Brian, chris, and damien took a math test that had 20 questions. the number of questions brian got right is 14 more than the number of questions chris got right. damien correctly answered 2 less than the number of questions chris answered correctly. if brian and damien have the same score, which statement is true?

Leslie started last week with $1200 in her checking account. during the week, she wrote the checks below.

Anyone? 15m is what percent of 60m; 3m; 30m; 1.5 km?