Slope = raise / run
(211.1 - 212.0) / (0.5-0) = - 1.8
(210.2 - 211.1) / (1.0-0.5) = - 1.8
(208.4 - 210.2) / (2.0 - 1.0) = - 1.8
You can check, the other points. The slope is constant because the function is a linear equation,
Answer: - 1.8
((4x+15)/(5x)) = 1/2
4x+15 = (5x)/2
8x+30=5x
3x+30=0
3x=-30
x=-10
