Since the rate of descent is a constant this is a linear equation and can be expressed as:
h=vt+b, where h=feet, v=slope or rate, b=y-intercept (y value when x=0 which is the initial height)
h=-2t+b, using the point (3,67) we can solve for b, or the initial height
67=-2(3)+b
67=-6+b
73=b so the initial height was 73 ft and the height equation is then:
h(t)=67-2t so when t=8 you have:
h(8)=67-2(8)
h(8)=67-16
h(8)=51 ft
