I need help finding out several things & show work

Question

x| 0| 1| 2| 3| 4| 5| 

y| 400| 340| 280| 220| 160| 100

 

find a rule 

find out what y equals when x equals 10 

 

Answer 1

Each time x increases by 1, y decreases by 60, so the relationship between x and y is linear.   Plotting the given points, we have a line with slope -60 and y-intercept (0, 400).  So, an equation of the line is:    

 

y = -60x + 400

 

When x = 10, y = -60(10) + 400 = -200