What is the solution to the systems of equations? equations - 3x-y= -17 , x-y= -13​

For the rule of 78, for a 12-month period, the last term in the sequence is 12 and the series sums to 78. for an 10 month period, the last term is and the series sum is . for a 15 month period, the last term is and the series sum is . for a 20 month period, the last term is and the series sum is

Write and solve a real word problem that involves determining distance on a coordinate plane

What are the exclude value of mn+3m