Uwu help pls lol TvT

You are a clerk at convenience store. a customer owes 11.69 for a bag of potatoes chips. she gives you a five dollar bill. how much change should the customer receive?

Find an equation of the line perpendicular to the graph of 28x-7y=9 that passes through the point at (4,1)

How do i start to solve? would appreciate a walk-thru! a bird sitting 16ft above the ground in an apple tree dislodges an apple. after how many seconds does the apple land on the ground? (assuming that no branches will interfere with it's fall)