Please help me (math) thank you so much!!

How do you solving the solution of each system using elimination?

If benito is selecting samples of five values from the table, which row will result in the greatest mean? population data row 1 4 2 2 3 3 row 2 3 3 4 3 2 row 3 2 4 3 4 3 row 4 3 4 4 7 3 row 1 row 2 r

Factor and solve to find roots x squared -x - 90 =0