A submarine is descending to examine the sea floor 2,10 feet below surface. It takes the submarine 2 hours to make this descent. Write an equation to represent the relationship between the submarines elevation and time.

Y=kx

Y = (105 ft/hr) x

Step-by-step explanation:

Where y is the elevation and x is the time,

k = y/x = 210/2 = 105 ft/hr

x = -3

y = -18

step-by-step explanation:

to solve by substitution, substitute one variable and solve for the other. then substitute again to find the remaining variable.

x-1/3(3x-9) = -3 since y=3x-9 substittute y.

x-1/3(3x-9)=-3

x + x +3 = -3

2x+3=-3

2x+3-3= -3-3

2x=-6

x=-3

substitute again into y=3x-9

y=3(-3)-9

y=-9-9

y=-18