The elevation at ground level is 0 feet an elevator starts 90 feet below ground level. after traveling for 15 seconds, the elevator is 20 feet below ground level. which statement describes the elevators rate of change in elevation during this 15 second interval?

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

the answer would be c:   ax + b = ax + c

step-by-step explanation:

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step-by-step explanation:

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