How is lightning to organisms? its science again

If (a, b) is the solution to the system of equations shown above, and a and b are integers, then what is the value of a+b?

The recommended daily calcium intake for a 20-year-old is 1,000 milligrams (mg). one cup of milk contains 299 mg of calcium and one cup of juice contains 261 mg of calcium. which of the following inequalities represents the possible number of cups of milk m and cups of juice j a 20-year-old could drink in a day to meet or exceed the recommended daily calcium intake from these drinks alone?

Asoccer team has played 25 games and has won 60% of the games it has played. what is the minimum number of additional games the team must win in order to finish the season winning 80% of the games it has played?