Please answer correctly

Which equation results from adding the equations in this system? x+6y=9 and -x+2y=-15

Helll ! 1,400 tons of wheat of two different varieties was delivered to the silo. when processing one variety, there was 2% of waste and 3% during the processing of the second variety of wheat. after the processing, the amount of remaining wheat was 1,364 tons. how many tons of each variety of wheat was delivered to the silo?

How do you find the distance of each number from the mean