Solve the system of linear equations using substitution.
x=7y-9
x+7y=3

Find the value of tan theta if sin theta = 12/13 and theta is in quadrant 2

There were 816 people at a concert when a band started to play. after each song, only half the people stayed to hear the next song. how many people were left at the concert after x songs? write a function to represent this scenario.

Determine which expressions represent real numbers and which expressions represent complex number. asaaap! plis!