Let x be the time and y is the depth
At x = 0 y = -130
At x= 6.5 y = 0
So the slope = (0- (-130) / ( 6.5 – 0) = 20
Y intercept b
0 = 20(6.5) + b
B= -130
The equation
Y = 20x -130
The domain all real numbers from 0 to 6.5
Range is all realnumber from -130 to 0